lavf: add SBG demuxer.

1 files changed, 1518 insertions, 0 deletions

diff --git a/libavformat/sbgdec.c b/libavformat/sbgdec.c
new file mode 100644
index 0000000..2ec8702
--- /dev/null
+++ b/libavformat/sbgdec.c
@@ -0,0 +1,1518 @@
+/*
+ * SBG (SBaGen) file format decoder
+ * Copyright (c) 2011 Nicolas George
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+#include "avformat.h"
+#include "internal.h"
+
+#define SBG_SCALE (1 << 16)
+#define DAY (24 * 60 * 60)
+#define DAY_TS ((int64_t)DAY * AV_TIME_BASE)
+
+struct sbg_demuxer {
+    AVClass *class;
+    int sample_rate;
+    int frame_size;
+    int max_file_size;
+};
+
+struct sbg_string {
+    char *s;
+    char *e;
+};
+
+enum sbg_fade_type {
+    SBG_FADE_SILENCE = 0,
+    SBG_FADE_SAME    = 1,
+    SBG_FADE_ADAPT   = 3,
+};
+
+struct sbg_fade {
+    int8_t in, out, slide;
+};
+
+enum sbg_synth_type {
+    SBG_TYPE_NONE,
+    SBG_TYPE_SINE,
+    SBG_TYPE_NOISE,
+    SBG_TYPE_BELL,
+    SBG_TYPE_MIX,
+    SBG_TYPE_SPIN,
+};
+
+/* bell: freq constant, ampl decreases exponentially, can be approx lin */
+
+struct sbg_timestamp {
+    int64_t t;
+    char type; /* 0 for relative, 'N' for now, 'T' for absolute */
+};
+
+struct sbg_script_definition {
+    char *name;
+    int name_len;
+    int elements, nb_elements;
+    char type; /* 'S' or 'B' */
+};
+
+struct sbg_script_synth {
+    int carrier;
+    int beat;
+    int vol;
+    enum sbg_synth_type type;
+    struct {
+        int l, r;
+    } ref;
+};
+
+struct sbg_script_tseq {
+    struct sbg_timestamp ts;
+    char *name;
+    int name_len;
+    int lock;
+    struct sbg_fade fade;
+};
+
+struct sbg_script_event {
+    int64_t ts;
+    int64_t ts_int, ts_trans, ts_next;
+    int elements, nb_elements;
+    struct sbg_fade fade;
+};
+
+struct sbg_script {
+    struct sbg_script_definition *def;
+    struct sbg_script_synth *synth;
+    struct sbg_script_tseq *tseq;
+    struct sbg_script_tseq *block_tseq;
+    struct sbg_script_event *events;
+    int nb_def;
+    int nb_tseq;
+    int nb_events;
+    int nb_synth;
+    int64_t start_ts;
+    int64_t end_ts;
+    int64_t opt_fade_time;
+    int64_t opt_duration;
+    char *opt_mix;
+    int sample_rate;
+    uint8_t opt_start_at_first;
+    uint8_t opt_end_at_last;
+};
+
+struct sbg_parser {
+    void *log;
+    char *script, *end;
+    char *cursor;
+    struct sbg_script scs;
+    struct sbg_timestamp current_time;
+    int nb_block_tseq;
+    int nb_def_max, nb_synth_max, nb_tseq_max, nb_block_tseq_max;
+    int line_no;
+    char err_msg[128];
+};
+
+enum ws_interval_type {
+    WS_SINE  = MKTAG('S','I','N','E'),
+    WS_NOISE = MKTAG('N','O','I','S'),
+};
+
+struct ws_interval {
+    int64_t ts1, ts2;
+    enum ws_interval_type type;
+    uint32_t channels;
+    int32_t f1, f2;
+    int32_t a1, a2;
+    uint32_t phi;
+};
+
+struct ws_intervals {
+    struct ws_interval *inter;
+    int nb_inter;
+    int max_inter;
+};
+
+static void *alloc_array_elem(void **array, size_t elsize,
+                              int *size, int *max_size)
+{
+    void *ret;
+
+    if (*size == *max_size) {
+        int m = FFMAX(32, FFMIN(*max_size, INT_MAX / 2) * 2);
+        if (*size >= m)
+            return NULL;
+        *array = av_realloc_f(*array, m, elsize);
+        if (!*array)
+            return NULL;
+        *max_size = m;
+    }
+    ret = (char *)*array + elsize * *size;
+    memset(ret, 0, elsize);
+    (*size)++;
+    return ret;
+}
+
+static int str_to_time(const char *str, int64_t *rtime)
+{
+    const char *cur = str;
+    char *end;
+    int hours, minutes;
+    double seconds = 0;
+
+    if (*cur < '0' || *cur > '9')
+        return 0;
+    hours = strtol(cur, &end, 10);
+    if (end == cur || *end != ':' || end[1] < '0' || end[1] > '9')
+        return 0;
+    cur = end + 1;
+    minutes = strtol(cur, &end, 10);
+    if (end == cur)
+        return 0;
+    cur = end;
+    if (*end == ':'){
+        seconds = strtod(cur + 1, &end);
+        if (end > cur + 1)
+            cur = end;
+    }
+    *rtime = (hours * 3600 + minutes * 60 + seconds) * AV_TIME_BASE;
+    return cur - str;
+}
+
+static inline int is_space(char c)
+{
+    return c == ' '  || c == '\t' || c == '\r';
+}
+
+static inline int scale_double(void *log, double d, double m, int *r)
+{
+    m *= d * SBG_SCALE;
+    if (m < INT_MIN || m >= INT_MAX) {
+        if (log)
+            av_log(log, AV_LOG_ERROR, "%g is too large\n", d);
+        return AVERROR(EDOM);
+    }
+    *r = m;
+    return 0;
+}
+
+static int lex_space(struct sbg_parser *p)
+{
+    char *c = p->cursor;
+
+    while (p->cursor < p->end && is_space(*p->cursor))
+        p->cursor++;
+    return p->cursor > c;
+}
+
+static int lex_char(struct sbg_parser *p, char c)
+{
+    int r = p->cursor < p->end && *p->cursor == c;
+
+    p->cursor += r;
+    return r;
+}
+
+static int lex_double(struct sbg_parser *p, double *r)
+{
+    double d;
+    char *end;
+
+    if (p->cursor == p->end || is_space(*p->cursor) || *p->cursor == '\n')
+        return 0;
+    d = strtod(p->cursor, &end);
+    if (end > p->cursor) {
+        *r = d;
+        p->cursor = end;
+        return 1;
+    }
+    return 0;
+}
+
+static int lex_fixed(struct sbg_parser *p, const char *t, int l)
+{
+    if (p->end - p->cursor < l || memcmp(p->cursor, t, l))
+        return 0;
+    p->cursor += l;
+    return 1;
+}
+
+static int lex_line_end(struct sbg_parser *p)
+{
+    if (p->cursor < p->end && *p->cursor == '#') {
+        p->cursor++;
+        while (p->cursor < p->end && *p->cursor != '\n')
+            p->cursor++;
+    }
+    if (p->cursor == p->end)
+        /* simulate final LF for files lacking it */
+        return 1;
+    if (*p->cursor != '\n')
+        return 0;
+    p->cursor++;
+    p->line_no++;
+    lex_space(p);
+    return 1;
+}
+
+static int lex_wsword(struct sbg_parser *p, struct sbg_string *rs)
+{
+    char *s = p->cursor, *c = s;
+
+    if (s == p->end || *s == '\n')
+        return 0;
+    while (c < p->end && *c != '\n' && !is_space(*c))
+        c++;
+    rs->s = s;
+    rs->e = p->cursor = c;
+    lex_space(p);
+    return 1;
+}
+
+static int lex_name(struct sbg_parser *p, struct sbg_string *rs)
+{
+    char *s = p->cursor, *c = s;
+
+    while (c < p->end && ((*c >= 'a' && *c <= 'z') || (*c >= 'A' && *c <= 'Z')
+           || (*c >= '0' && *c <= '9') || *c == '_' || *c == '-'))
+        c++;
+    if (c == s)
+        return 0;
+    rs->s = s;
+    rs->e = p->cursor = c;
+    return 1;
+}
+
+static int lex_time(struct sbg_parser *p, int64_t *rt)
+{
+    int r = str_to_time(p->cursor, rt);
+    p->cursor += r;
+    return r > 0;
+}
+
+#define FORWARD_ERROR(c) \
+    do { \
+        int errcode = c; \
+        if (errcode <= 0) \
+            return errcode ? errcode : AVERROR_INVALIDDATA; \
+    } while(0);
+
+static int parse_immediate(struct sbg_parser *p)
+{
+    snprintf(p->err_msg, sizeof(p->err_msg),
+             "immediate sequences not yet implemented");
+    return AVERROR_PATCHWELCOME;
+}
+
+static int parse_preprogrammed(struct sbg_parser *p)
+{
+    snprintf(p->err_msg, sizeof(p->err_msg),
+             "preprogrammed sequences not yet implemented");
+    return AVERROR_PATCHWELCOME;
+}
+
+static int parse_optarg(struct sbg_parser *p, char o, struct sbg_string *r)
+{
+    if (!lex_wsword(p, r)) {
+        snprintf(p->err_msg, sizeof(p->err_msg),
+                 "option '%c' requires an argument", o);
+        return AVERROR_INVALIDDATA;
+    }
+    return 1;
+}
+
+static int parse_options(struct sbg_parser *p)
+{
+    struct sbg_string ostr, oarg;
+    char mode = 0;
+    int r;
+    char *tptr;
+    double v;
+
+    if (p->cursor == p->end || *p->cursor != '-')
+        return 0;
+    while (lex_char(p, '-') && lex_wsword(p, &ostr)) {
+        for (; ostr.s < ostr.e; ostr.s++) {
+            char opt = *ostr.s;
+            switch (opt) {
+                case 'S':
+                    p->scs.opt_start_at_first = 1;
+                    break;
+                case 'E':
+                    p->scs.opt_end_at_last = 1;
+                    break;
+                case 'i':
+                    mode = 'i';
+                    break;
+                case 'p':
+                    mode = 'p';
+                    break;
+                case 'F':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    v = strtod(oarg.s, &tptr);
+                    if (oarg.e != tptr) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "syntax error for option -F");
+                        return AVERROR_INVALIDDATA;
+                    }
+                    p->scs.opt_fade_time = v * AV_TIME_BASE / 1000;
+                    break;
+                case 'L':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    r = str_to_time(oarg.s, &p->scs.opt_duration);
+                    if (oarg.e != oarg.s + r) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "syntax error for option -L");
+                        return AVERROR_INVALIDDATA;
+                    }
+                    break;
+                case 'T':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    r = str_to_time(oarg.s, &p->scs.start_ts);
+                    if (oarg.e != oarg.s + r) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "syntax error for option -T");
+                        return AVERROR_INVALIDDATA;
+                    }
+                    break;
+                case 'm':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    tptr = av_malloc(oarg.e - oarg.s + 1);
+                    if (!tptr)
+                        return AVERROR(ENOMEM);
+                    memcpy(tptr, oarg.s, oarg.e - oarg.s);
+                    tptr[oarg.e - oarg.s] = 0;
+                    av_free(p->scs.opt_mix);
+                    p->scs.opt_mix = tptr;
+                    break;
+                case 'q':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    v = strtod(oarg.s, &tptr);
+                    if (oarg.e != tptr) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "syntax error for option -q");
+                        return AVERROR_INVALIDDATA;
+                    }
+                    if (v != 1) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "speed factor other than 1 not supported");
+                        return AVERROR_PATCHWELCOME;
+                    }
+                    break;
+                case 'r':
+                    FORWARD_ERROR(parse_optarg(p, opt, &oarg));
+                    r = strtol(oarg.s, &tptr, 10);
+                    if (oarg.e != tptr) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "syntax error for option -r");
+                        return AVERROR_INVALIDDATA;
+                    }
+                    if (r < 40) {
+                        snprintf(p->err_msg, sizeof(p->err_msg),
+                                 "invalid sample rate");
+                        return AVERROR_PATCHWELCOME;
+                    }
+                    p->scs.sample_rate = r;
+                    break;
+                default:
+                    snprintf(p->err_msg, sizeof(p->err_msg),
+                             "unknown option: '%c'", *ostr.s);
+                    return AVERROR_INVALIDDATA;
+            }
+        }
+    }
+    switch (mode) {
+        case 'i':
+            return parse_immediate(p);
+        case 'p':
+            return parse_preprogrammed(p);
+        case 0:
+            if (!lex_line_end(p))
+                return AVERROR_INVALIDDATA;
+            return 1;
+    }
+    return AVERROR_BUG;
+}
+
+static int parse_timestamp(struct sbg_parser *p,
+                               struct sbg_timestamp *rts, int64_t *rrel)
+{
+    int64_t abs = 0, rel = 0, dt;
+    char type = 0;
+    int r;
+
+    if (lex_fixed(p, "NOW", 3)) {
+        type = 'N';
+        r = 1;
+    } else {
+        r = lex_time(p, &abs);
+        if (r)
+            type = 'T';
+    }
+    while (lex_char(p, '+')) {
+        if (!lex_time(p, &dt))
+            return AVERROR_INVALIDDATA;
+        rel += dt;
+        r = 1;
+    }
+    if (r) {
+        if (!lex_space(p))
+            return AVERROR_INVALIDDATA;
+        rts->type = type;
+        rts->t    = abs;
+        *rrel     = rel;
+    }
+    return r;
+}
+
+static int parse_fade(struct sbg_parser *p, struct sbg_fade *fr)
+{
+    struct sbg_fade f;
+
+    if (lex_char(p, '<'))
+        f.in = SBG_FADE_SILENCE;
+    else if (lex_char(p, '-'))
+        f.in = SBG_FADE_SAME;
+    else if (lex_char(p, '='))
+        f.in = SBG_FADE_ADAPT;
+    else
+        return 0;
+    if (lex_char(p, '>'))
+        f.out = SBG_FADE_SILENCE;
+    else if (lex_char(p, '-'))
+        f.out = SBG_FADE_SAME;
+    else if (lex_char(p, '='))
+        f.out = SBG_FADE_ADAPT;
+    else
+        return AVERROR_INVALIDDATA;
+    *fr = f;
+    return 1;
+}
+
+static int parse_time_sequence(struct sbg_parser *p, int inblock)
+{
+    struct sbg_timestamp ts;
+    int64_t rel_ts;
+    int r;
+    struct sbg_fade fade = { SBG_FADE_SAME, SBG_FADE_SAME, 0 };
+    struct sbg_string name;
+    struct sbg_script_tseq *tseq;
+
+    r = parse_timestamp(p, &ts, &rel_ts);
+    if (!r)
+        return 0;
+    if (r < 0)
+        return r;
+    if (ts.type) {
+        if (inblock)
+            return AVERROR_INVALIDDATA;
+        p->current_time.type = ts.type;
+        p->current_time.t    = ts.t;
+    } else if(!inblock && !p->current_time.type) {
+        snprintf(p->err_msg, sizeof(p->err_msg),
+                 "relative time without previous absolute time");
+        return AVERROR_INVALIDDATA;
+    }
+    ts.type = p->current_time.type;
+    ts.t    = p->current_time.t + rel_ts;
+    r = parse_fade(p, &fade);
+    if (r < 0)
+        return r;
+    lex_space(p);
+    if (!lex_name(p, &name))
+        return AVERROR_INVALIDDATA;
+    lex_space(p);
+    if (lex_fixed(p, "->", 2)) {
+        fade.slide = SBG_FADE_ADAPT;
+        lex_space(p);
+    }
+    if (!lex_line_end(p))
+        return AVERROR_INVALIDDATA;
+    tseq = inblock ?
+           alloc_array_elem((void **)&p->scs.block_tseq, sizeof(*tseq),
+                            &p->nb_block_tseq, &p->nb_block_tseq_max) :
+           alloc_array_elem((void **)&p->scs.tseq, sizeof(*tseq),
+                            &p->scs.nb_tseq, &p->nb_tseq_max);
+    if (!tseq)
+        return AVERROR(ENOMEM);
+    tseq->ts       = ts;
+    tseq->name     = name.s;
+    tseq->name_len = name.e - name.s;
+    tseq->fade     = fade;
+    return 1;
+}
+
+static int parse_wave_def(struct sbg_parser *p, int wavenum)
+{
+    snprintf(p->err_msg, sizeof(p->err_msg),
+             "waveform definitions not yet implemented");
+    return AVERROR_PATCHWELCOME;
+}
+
+static int parse_block_def(struct sbg_parser *p,
+                           struct sbg_script_definition *def)
+{
+    int r, tseq;
+
+    lex_space(p);
+    if (!lex_line_end(p))
+        return AVERROR_INVALIDDATA;
+    tseq = p->nb_block_tseq;
+    while (1) {
+        r = parse_time_sequence(p, 1);
+        if (r < 0)
+            return r;
+        if (!r)
+            break;
+    }
+    if (!lex_char(p, '}'))
+        return AVERROR_INVALIDDATA;
+    lex_space(p);
+    if (!lex_line_end(p))
+        return AVERROR_INVALIDDATA;
+    def->type        = 'B';
+    def->elements    = tseq;
+    def->nb_elements = p->nb_block_tseq - tseq;
+    if (!def->nb_elements)
+        return AVERROR_INVALIDDATA;
+    return 1;
+}
+
+static int parse_volume(struct sbg_parser *p, int *vol)
+{
+    double v;
+
+    if (!lex_char(p, '/'))
+        return 0;
+    if (!lex_double(p, &v))
+        return AVERROR_INVALIDDATA;
+    if (scale_double(p->log, v, 0.01, vol))
+        return AVERROR(ERANGE);
+    return 1;
+}
+
+static int parse_synth_channel_sine(struct sbg_parser *p,
+                                    struct sbg_script_synth *synth)
+{
+    double carrierf, beatf;
+    int carrier, beat, vol;
+
+    if (!lex_double(p, &carrierf))
+        return 0;
+    if (!lex_double(p, &beatf))
+        beatf = 0;
+    FORWARD_ERROR(parse_volume(p, &vol));
+    if (scale_double(p->log, carrierf, 1, &carrier) < 0 ||
+        scale_double(p->log, beatf, 1, &beat) < 0)
+        return AVERROR(EDOM);
+    synth->type    = SBG_TYPE_SINE;
+    synth->carrier = carrier;
+    synth->beat    = beat;
+    synth->vol     = vol;
+    return 1;
+}
+
+static int parse_synth_channel_pink(struct sbg_parser *p,
+                                    struct sbg_script_synth *synth)
+{
+    int vol;
+
+    if (!lex_fixed(p, "pink", 4))
+        return 0;
+    FORWARD_ERROR(parse_volume(p, &vol));
+    synth->type    = SBG_TYPE_NOISE;
+    synth->vol     = vol;
+    return 1;
+}
+
+static int parse_synth_channel_bell(struct sbg_parser *p,
+                                    struct sbg_script_synth *synth)
+{
+    double carrierf;
+    int carrier, vol;
+
+    if (!lex_fixed(p, "bell", 4))
+        return 0;
+    if (!lex_double(p, &carrierf))
+        return AVERROR_INVALIDDATA;
+    FORWARD_ERROR(parse_volume(p, &vol));
+    if (scale_double(p->log, carrierf, 1, &carrier) < 0)
+        return AVERROR(EDOM);
+    synth->type    = SBG_TYPE_BELL;
+    synth->carrier = carrier;
+    synth->vol     = vol;
+    return 1;
+}
+
+static int parse_synth_channel_mix(struct sbg_parser *p,
+                                   struct sbg_script_synth *synth)
+{
+    int vol;
+
+    if (!lex_fixed(p, "mix", 3))
+        return 0;
+    FORWARD_ERROR(parse_volume(p, &vol));
+    synth->type    = SBG_TYPE_MIX;
+    synth->vol     = vol;
+    return 1;
+}
+
+static int parse_synth_channel_spin(struct sbg_parser *p,
+                                    struct sbg_script_synth *synth)
+{
+    double carrierf, beatf;
+    int carrier, beat, vol;
+
+    if (!lex_fixed(p, "spin:", 5))
+        return 0;
+    if (!lex_double(p, &carrierf))
+        return AVERROR_INVALIDDATA;
+    if (!lex_double(p, &beatf))
+        return AVERROR_INVALIDDATA;
+    FORWARD_ERROR(parse_volume(p, &vol));
+    if (scale_double(p->log, carrierf, 1, &carrier) < 0 ||
+        scale_double(p->log, beatf, 1, &beat) < 0)
+        return AVERROR(EDOM);
+    synth->type    = SBG_TYPE_SPIN;
+    synth->carrier = carrier;
+    synth->beat    = beat;
+    synth->vol     = vol;
+    return 1;
+}
+
+static int parse_synth_channel(struct sbg_parser *p)
+{
+    int r;
+    struct sbg_script_synth *synth;
+
+    synth = alloc_array_elem((void **)&p->scs.synth, sizeof(*synth),
+                             &p->scs.nb_synth, &p->nb_synth_max);
+    if (!synth)
+        return AVERROR(ENOMEM);
+    r = lex_char(p, '-');
+    if (!r)
+        r = parse_synth_channel_pink(p, synth);
+    if (!r)
+        r = parse_synth_channel_bell(p, synth);
+    if (!r)
+        r = parse_synth_channel_mix(p, synth);
+    if (!r)
+        r = parse_synth_channel_spin(p, synth);
+    /* Unimplemented: wave%d:%f%f/vol (carrier, beat) */
+    if (!r)
+        r = parse_synth_channel_sine(p, synth);
+    if (r <= 0)
+        p->scs.nb_synth--;
+    return r;
+}
+
+static int parse_synth_def(struct sbg_parser *p,
+                           struct sbg_script_definition *def)
+{
+    int r, synth;
+
+    synth = p->scs.nb_synth;
+    while (1) {
+        r = parse_synth_channel(p);
+        if (r < 0)
+            return r;
+        if (!r || !lex_space(p))
+            break;
+    }
+    lex_space(p);
+    if (synth == p->scs.nb_synth)
+        return AVERROR_INVALIDDATA;
+    if (!lex_line_end(p))
+        return AVERROR_INVALIDDATA;
+    def->type        = 'S';
+    def->elements    = synth;
+    def->nb_elements = p->scs.nb_synth - synth;
+    return 1;
+}
+
+static int parse_named_def(struct sbg_parser *p)
+{
+    char *cursor_save = p->cursor;
+    struct sbg_string name;
+    struct sbg_script_definition *def;
+
+    if (!lex_name(p, &name) || !lex_char(p, ':') || !lex_space(p)) {
+        p->cursor = cursor_save;
+        return 0;
+    }
+    if (name.e - name.s == 6 && !memcmp(name.s, "wave", 4) &&
+        name.s[4] >= '0' && name.s[4] <= '9' &&
+        name.s[5] >= '0' && name.s[5] <= '9') {
+        int wavenum = (name.s[4] - '0') * 10 + (name.s[5] - '0');
+        return parse_wave_def(p, wavenum);
+    }
+    def = alloc_array_elem((void **)&p->scs.def, sizeof(*def),
+                           &p->scs.nb_def, &p->nb_def_max);
+    if (!def)
+        return AVERROR(ENOMEM);
+    def->name     = name.s;
+    def->name_len = name.e - name.s;
+    if (lex_char(p, '{'))
+        return parse_block_def(p, def);
+    return parse_synth_def(p, def);
+}
+
+static void free_script(struct sbg_script *s)
+{
+    av_freep(&s->def);
+    av_freep(&s->synth);
+    av_freep(&s->tseq);
+    av_freep(&s->block_tseq);
+    av_freep(&s->events);
+    av_freep(&s->opt_mix);
+}
+
+static int parse_script(void *log, char *script, int script_len,
+                            struct sbg_script *rscript)
+{
+    struct sbg_parser sp = {
+        .log     = log,
+        .script  = script,
+        .end     = script + script_len,
+        .cursor  = script,
+        .line_no = 1,
+        .err_msg = "",
+        .scs = {
+            /* default values */
+            .start_ts      = AV_NOPTS_VALUE,
+            .sample_rate   = 44100,
+            .opt_fade_time = 60 * AV_TIME_BASE,
+        },
+    };
+    int r;
+
+    lex_space(&sp);
+    while (sp.cursor < sp.end) {
+        r = parse_options(&sp);
+        if (r < 0)
+            goto fail;
+        if (!r && !lex_line_end(&sp))
+            break;
+    }
+    while (sp.cursor < sp.end) {
+        r = parse_named_def(&sp);
+        if (!r)
+            r = parse_time_sequence(&sp, 0);
+        if (!r)
+            r = lex_line_end(&sp) ? 1 : AVERROR_INVALIDDATA;
+        if (r < 0)
+            goto fail;
+    }
+    *rscript = sp.scs;
+    return 1;
+fail:
+    free_script(&sp.scs);
+    if (!*sp.err_msg)
+        if (r == AVERROR_INVALIDDATA)
+            snprintf(sp.err_msg, sizeof(sp.err_msg), "syntax error");
+    if (log && *sp.err_msg) {
+        const char *ctx = sp.cursor;
+        const char *ectx = av_x_if_null(memchr(ctx, '\n', sp.end - sp.cursor),
+                                        sp.end);
+        int lctx = ectx - ctx;
+        const char *quote = "\"";
+        if (lctx > 0 && ctx[lctx - 1] == '\r')
+            lctx--;
+        if (lctx == 0) {
+            ctx = "the end of line";
+            lctx = strlen(ctx);
+            quote = "";
+        }
+        av_log(log, AV_LOG_ERROR, "Error line %d: %s near %s%.*s%s.\n",
+               sp.line_no, sp.err_msg, quote, lctx, ctx, quote);
+    }
+    return r;
+}
+
+static int read_whole_file(AVIOContext *io, int max_size, char **rbuf)
+{
+    char *buf = NULL;
+    int size = 0, bufsize = 0, r;
+
+    while (1) {
+        if (bufsize - size < 1024) {
+            bufsize = FFMIN(FFMAX(2 * bufsize, 8192), max_size);
+            if (bufsize - size < 2) {
+                size = AVERROR(EFBIG);
+                goto fail;
+            }
+            buf = av_realloc_f(buf, bufsize, 1);
+            if (!buf) {
+                size = AVERROR(ENOMEM);
+                goto fail;
+            }
+        }
+        r = avio_read(io, buf, bufsize - size - 1);
+        if (r == AVERROR_EOF)
+            break;
+        if (r < 0)
+            goto fail;
+        size += r;
+    }
+    buf[size] = 0;
+    *rbuf = buf;
+    return size;
+fail:
+    av_free(buf);
+    return size;
+}
+
+static void expand_timestamps(void *log, struct sbg_script *s)
+{
+    int i, nb_rel = 0;
+    int64_t now, cur_ts, delta = 0;
+
+    for (i = 0; i < s->nb_tseq; i++)
+        nb_rel += s->tseq[i].ts.type == 'N';
+    if (nb_rel == s->nb_tseq) {
+        /* All ts are relative to NOW: consider NOW = 0 */
+        now = 0;
+        if (s->start_ts != AV_NOPTS_VALUE)
+            av_log(log, AV_LOG_WARNING,
+                   "Start time ignored in a purely relative script.\n");
+    } else if (nb_rel == 0 && s->start_ts != AV_NOPTS_VALUE ||
+               s->opt_start_at_first) {
+        /* All ts are absolute and start time is specified */
+        if (s->start_ts == AV_NOPTS_VALUE)
+            s->start_ts = s->tseq[0].ts.t;
+        now = s->start_ts;
+    } else {
+        /* Mixed relative/absolute ts: expand */
+        time_t now0;
+        struct tm *tm;
+
+        av_log(log, AV_LOG_WARNING,
+               "Scripts with mixed absolute and relative timestamps can give "
+               "unexpected results (pause, seeking, time zone change).\n");
+#undef time
+        time(&now0);
+        tm = localtime(&now0);
+        now = tm ? tm->tm_hour * 3600 + tm->tm_min * 60 + tm->tm_sec :
+                   now0 % DAY;
+        av_log(log, AV_LOG_INFO, "Using %02d:%02d:%02d as NOW.\n",
+               (int)(now / 3600), (int)(now / 60) % 60, (int)now % 60);
+        now *= AV_TIME_BASE;
+        for (i = 0; i < s->nb_tseq; i++) {
+            if (s->tseq[i].ts.type == 'N') {
+                s->tseq[i].ts.t += now;
+                s->tseq[i].ts.type = 'T'; /* not necessary */
+            }
+        }
+    }
+    if (s->start_ts == AV_NOPTS_VALUE)
+        s->start_ts = s->opt_start_at_first ? s->tseq[0].ts.t : now;
+    s->end_ts = s->opt_duration ? s->start_ts + s->opt_duration :
+                AV_NOPTS_VALUE; /* may be overridden later by -E option */
+    cur_ts = now;
+    for (i = 0; i < s->nb_tseq; i++) {
+        if (s->tseq[i].ts.t + delta < cur_ts)
+            delta += DAY_TS;
+        cur_ts = s->tseq[i].ts.t += delta;
+    }
+}
+
+static int expand_tseq(void *log, struct sbg_script *s, int *nb_ev_max,
+                       int64_t t0, struct sbg_script_tseq *tseq)
+{
+    int i, r;
+    struct sbg_script_definition *def;
+    struct sbg_script_tseq *be;
+    struct sbg_script_event *ev;
+
+    if (tseq->lock++) {
+        av_log(log, 16, "Recursion loop on \"%.*s\"\n",
+               tseq->name_len, tseq->name);
+        return AVERROR(ELOOP);
+    }
+    t0 += tseq->ts.t;
+    for (i = 0; i < s->nb_def; i++) {
+        if (s->def[i].name_len == tseq->name_len &&
+            !memcmp(s->def[i].name, tseq->name, tseq->name_len))
+            break;
+    }
+    if (i >= s->nb_def) {
+        av_log(log, 16, "Tone-set \"%.*s\" not defined\n",
+               tseq->name_len, tseq->name);
+        return AVERROR(EINVAL);
+    }
+    def = &s->def[i];
+    if (def->type == 'B') {
+        be = s->block_tseq + def->elements;
+        for (i = 0; i < def->nb_elements; i++) {
+            r = expand_tseq(log, s, nb_ev_max, t0, &be[i]);
+            if (r < 0)
+                return r;
+        }
+    } else {
+        ev = alloc_array_elem((void **)&s->events, sizeof(*ev),
+                              &s->nb_events, nb_ev_max);
+        ev->ts          = tseq->ts.t;
+        ev->elements    = def->elements;
+        ev->nb_elements = def->nb_elements;
+        ev->fade        = tseq->fade;
+    }
+    tseq->lock--;
+    return 0;
+}
+
+static int expand_script(void *log, struct sbg_script *s)
+{
+    int i, r, nb_events_max = 0;
+
+    expand_timestamps(log, s);
+    for (i = 0; i < s->nb_tseq; i++) {
+        r = expand_tseq(log, s, &nb_events_max, 0, &s->tseq[i]);
+        if (r < 0)
+            return r;
+    }
+    if (!s->nb_events) {
+        av_log(log, AV_LOG_ERROR, "No events in script\n");
+        return AVERROR_INVALIDDATA;
+    }
+    if (s->opt_end_at_last)
+        s->end_ts = s->events[s->nb_events - 1].ts;
+    return 0;
+}
+
+static int add_interval(struct ws_intervals *inter,
+                        enum ws_interval_type type, uint32_t channels, int ref,
+                        int64_t ts1, int32_t f1, int32_t a1,
+                        int64_t ts2, int32_t f2, int32_t a2)
+{
+    struct ws_interval *i, *ri;
+
+    if (ref >= 0) {
+        ri = &inter->inter[ref];
+        /* ref and new intervals are constant, identical and adjacent */
+        if (ri->type == type && ri->channels == channels &&
+            ri->f1 == ri->f2 && ri->f2 == f1 && f1 == f2 &&
+            ri->a1 == ri->a2 && ri->a2 == a1 && a1 == a2 &&
+            ri->ts2 == ts1) {
+            ri->ts2 = ts2;
+            return ref;
+        }
+    }
+    i = alloc_array_elem((void **)&inter->inter, sizeof(*i),
+                         &inter->nb_inter, &inter->max_inter);
+    if (!i)
+        return AVERROR(ENOMEM);
+    i->ts1      = ts1;
+    i->ts2      = ts2;
+    i->type     = type;
+    i->channels = channels;
+    i->f1       = f1;
+    i->f2       = f2;
+    i->a1       = a1;
+    i->a2       = a2;
+    i->phi      = ref >= 0 ? ref | 0x80000000 : 0;
+    return i - inter->inter;
+}
+
+static int add_bell(struct ws_intervals *inter, struct sbg_script *s,
+                    int64_t ts1, int64_t ts2, int32_t f, int32_t a)
+{
+    /* SBaGen uses an exponential decrease every 50ms.
+       We approximate it with piecewise affine segments. */
+    int32_t cpoints[][2] = {
+        {  2, a },
+        {  4, a - a / 4 },
+        {  8, a / 2 },
+        { 16, a / 4 },
+        { 25, a / 10 },
+        { 50, a / 80 },
+        { 75, 0 },
+    };
+    int i, r;
+    int64_t dt = s->sample_rate / 20, ts3 = ts1, ts4;
+    for (i = 0; i < FF_ARRAY_ELEMS(cpoints); i++) {
+        ts4 = FFMIN(ts2, ts1 + cpoints[i][0] * dt);
+        r = add_interval(inter, WS_SINE, 3, -1,
+                         ts3, f, a, ts4, f, cpoints[i][1]);
+        if (r < 0)
+            return r;
+        ts3 = ts4;
+        a = cpoints[i][1];
+    }
+    return 0;
+}
+
+static int generate_interval(void *log, struct sbg_script *s,
+                             struct ws_intervals *inter,
+                             int64_t ts1, int64_t ts2,
+                             struct sbg_script_synth *s1,
+                             struct sbg_script_synth *s2,
+                             int transition)
+{
+    int r;
+
+    if (ts2 <= ts1 || (s1->vol == 0 && s2->vol == 0))
+        return 0;
+    switch (s1->type) {
+        case SBG_TYPE_NONE:
+            break;
+        case SBG_TYPE_SINE:
+            if (s1->beat == 0 && s2->beat == 0) {
+                r = add_interval(inter, WS_SINE, 3, s1->ref.l,
+                                 ts1, s1->carrier, s1->vol,
+                                 ts2, s2->carrier, s2->vol);
+                if (r < 0)
+                    return r;
+                s2->ref.l = s2->ref.r = r;
+            } else {
+                r = add_interval(inter, WS_SINE, 1, s1->ref.l,
+                                 ts1, s1->carrier + s1->beat / 2, s1->vol,
+                                 ts2, s2->carrier + s2->beat / 2, s2->vol);
+                if (r < 0)
+                    return r;
+                s2->ref.l = r;
+                r = add_interval(inter, WS_SINE, 2, s1->ref.r,
+                                 ts1, s1->carrier - s1->beat / 2, s1->vol,
+                                 ts2, s2->carrier - s2->beat / 2, s2->vol);
+                if (r < 0)
+                    return r;
+                s2->ref.r = r;
+            }
+            break;
+
+        case SBG_TYPE_BELL:
+            if (transition == 2) {
+                r = add_bell(inter, s, ts1, ts2, s1->carrier, s2->vol);
+                if (r < 0)
+                    return r;
+            }
+            break;
+
+        case SBG_TYPE_SPIN:
+            av_log(log, AV_LOG_WARNING, "Spinning noise not implemented, "
+                                        "using pink noise instead.\n");
+            /* fall through */
+        case SBG_TYPE_NOISE:
+            /* SBaGen's pink noise generator uses:
+               - 1 band of white noise, mean square: 1/3;
+               - 9 bands of subsampled white noise with linear
+                 interpolation, mean square: 2/3 each;
+               with 1/10 weight each: the total mean square is 7/300.
+               Our pink noise generator uses 8 bands of white noise with
+               rectangular subsampling: the total mean square is 1/24.
+               Therefore, to match SBaGen's volume, we must multiply vol by
+               sqrt((7/300) / (1/24)) = sqrt(14/25) =~ 0.748
+             */
+            r = add_interval(inter, WS_NOISE, 3, s1->ref.l,
+                             ts1, 0, s1->vol - s1->vol / 4,
+                             ts2, 0, s2->vol - s2->vol / 4);
+            if (r < 0)
+                return r;
+            s2->ref.l = s2->ref.r = r;
+            break;
+
+        case SBG_TYPE_MIX:
+            /* Unimplemented: silence; warning present elsewhere */
+        default:
+            av_log(log, AV_LOG_ERROR,
+                   "Type %d is not implemented\n", s1->type);
+            return AVERROR_PATCHWELCOME;
+    }
+    return 0;
+}
+
+static int generate_plateau(void *log, struct sbg_script *s,
+                            struct ws_intervals *inter,
+                            struct sbg_script_event *ev1)
+{
+    int64_t ts1 = ev1->ts_int, ts2 = ev1->ts_trans;
+    int i, r;
+    struct sbg_script_synth *s1;
+
+    for (i = 0; i < ev1->nb_elements; i++) {
+        s1 = &s->synth[ev1->elements + i];
+        r = generate_interval(log, s, inter, ts1, ts2, s1, s1, 0);
+        if (r < 0)
+            return r;
+    }
+    return 0;
+}
+
+/*
+
+   ts1             ts2         ts1    tsmid    ts2
+    |               |           |       |       |
+    v               v           v       |       v
+____                        ____        v       ____
+    ''''....                    ''..        ..''
+            ''''....____            ''....''
+
+  compatible transition      incompatible transition
+ */
+
+static int generate_transition(void *log, struct sbg_script *s,
+                               struct ws_intervals *inter,
+                               struct sbg_script_event *ev1,
+                               struct sbg_script_event *ev2)
+{
+    int64_t ts1 = ev1->ts_trans, ts2 = ev1->ts_next;
+    /* (ts1 + ts2) / 2 without overflow */
+    int64_t tsmid = (ts1 >> 1) + (ts2 >> 1) + (ts1 & ts2 & 1);
+    enum sbg_fade_type type = ev1->fade.slide | (ev1->fade.out & ev2->fade.in);
+    int nb_elements = FFMAX(ev1->nb_elements, ev2->nb_elements);
+    struct sbg_script_synth *s1, *s2, s1mod, s2mod, smid;
+    int pass, i, r;
+
+    for (pass = 0; pass < 2; pass++) {
+        /* pass = 0 -> compatible and first half of incompatible
+           pass = 1 -> second half of incompatible
+           Using two passes like that ensures that the intervals are generated
+           in increasing order according to their start timestamp.
+           Otherwise it would be necessary to sort them
+           while keeping the mutual references.
+         */
+        for (i = 0; i < nb_elements; i++) {
+            s1 = i < ev1->nb_elements ? &s->synth[ev1->elements + i] : &s1mod;
+            s2 = i < ev2->nb_elements ? &s->synth[ev2->elements + i] : &s2mod;
+            s1mod = s1 != &s1mod ? *s1 : (struct sbg_script_synth){ 0 };
+            s2mod = s2 != &s2mod ? *s2 : (struct sbg_script_synth){ 0 };
+            if (ev1->fade.slide) {
+                /* for slides, and only for slides, silence ("-") is equivalent
+                   to anything with volume 0 */
+                if (s1mod.type == SBG_TYPE_NONE) {
+                    s1mod = s2mod;
+                    s1mod.vol = 0;
+                } else if (s2mod.type == SBG_TYPE_NONE) {
+                    s2mod = s1mod;
+                    s2mod.vol = 0;
+                }
+            }
+            if (s1mod.type == s2mod.type &&
+                s1mod.type != SBG_TYPE_BELL &&
+                (type == SBG_FADE_ADAPT ||
+                 (s1mod.carrier == s2mod.carrier &&
+                  s1mod.beat == s2mod.beat))) {
+                /* compatible: single transition */
+                if (!pass) {
+                    r = generate_interval(log, s, inter,
+                                          ts1, ts2, &s1mod, &s2mod, 3);
+                    if (r < 0)
+                        return r;
+                    s2->ref = s2mod.ref;
+                }
+            } else {
+                /* incompatible: silence at midpoint */
+                if (!pass) {
+                    smid = s1mod;
+                    smid.vol = 0;
+                    r = generate_interval(log, s, inter,
+                                          ts1, tsmid, &s1mod, &smid, 1);
+                    if (r < 0)
+                        return r;
+                } else {
+                    smid = s2mod;
+                    smid.vol = 0;
+                    r = generate_interval(log, s, inter,
+                                          tsmid, ts2, &smid, &s2mod, 2);
+                    if (r < 0)
+                        return r;
+                    s2->ref = s2mod.ref;
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+/*
+    ev1                  trats ev2  intts           endts ev3
+     |                     |    |     |               |    |
+     v                     v    v     v               v    v
+                                      ________________
+....                              ....                ....
+    '''....________________....'''                        '''...._______________
+
+\_________/\______________/\_________/\______________/\_________/\_____________/
+  tr x->1        int1        tr 1->2        int2        tr 2->3        int3
+ */
+
+static int generate_intervals(void *log, struct sbg_script *s, int sample_rate,
+                              struct ws_intervals *inter)
+{
+    int64_t trans_time = s->opt_fade_time / 2;
+    struct sbg_script_event ev0, *ev1, *ev2;
+    int64_t period;
+    int i, r;
+
+    /* SBaGen handles the time before and after the extremal events,
+       and the corresponding transitions, as if the sequence were cyclic
+       with a 24-hours period. */
+    period = s->events[s->nb_events - 1].ts - s->events[0].ts;
+    period = (period + (DAY_TS - 1)) / DAY_TS * DAY_TS;
+    period = FFMAX(period, DAY_TS);
+
+    /* Prepare timestamps for transitions */
+    for (i = 0; i < s->nb_events; i++) {
+        ev1 = &s->events[i];
+        ev2 = &s->events[(i + 1) % s->nb_events];
+        ev1->ts_int   = ev1->ts;
+        ev1->ts_trans = ev1->fade.slide ? ev1->ts
+                                        : ev2->ts + (ev1 < ev2 ? 0 : period);
+    }
+    for (i = 0; i < s->nb_events; i++) {
+        ev1 = &s->events[i];
+        ev2 = &s->events[(i + 1) % s->nb_events];
+        if (!ev1->fade.slide) {
+            ev1->ts_trans = FFMAX(ev1->ts_int,   ev1->ts_trans - trans_time);
+            ev2->ts_int   = FFMIN(ev2->ts_trans, ev2->ts_int   + trans_time);
+        }
+        ev1->ts_next  = ev2->ts_int + (ev1 < ev2 ? 0 : period);
+    }
+
+    /* Pseudo event before the first one */
+    ev0 = s->events[s->nb_events - 1];
+    ev0.ts_int   -= period;
+    ev0.ts_trans -= period;
+    ev0.ts_next  -= period;
+
+    /* Convert timestamps */
+    for (i = -1; i < s->nb_events; i++) {
+        ev1 = i < 0 ? &ev0 : &s->events[i];
+        ev1->ts_int   = av_rescale(ev1->ts_int,   sample_rate, AV_TIME_BASE);
+        ev1->ts_trans = av_rescale(ev1->ts_trans, sample_rate, AV_TIME_BASE);
+        ev1->ts_next  = av_rescale(ev1->ts_next,  sample_rate, AV_TIME_BASE);
+    }
+
+    /* Generate intervals */
+    for (i = 0; i < s->nb_synth; i++)
+        s->synth[i].ref.l = s->synth[i].ref.r = -1;
+    for (i = -1; i < s->nb_events; i++) {
+        ev1 = i < 0 ? &ev0 : &s->events[i];
+        ev2 = &s->events[(i + 1) % s->nb_events];
+        r = generate_plateau(log, s, inter, ev1);
+        if (r < 0)
+            return r;
+        r = generate_transition(log, s, inter, ev1, ev2);
+        if (r < 0)
+            return r;
+    }
+    if (!inter->nb_inter)
+        av_log(log, AV_LOG_WARNING, "Completely silent script.\n");
+    return 0;
+}
+
+static int encode_intervals(struct sbg_script *s, AVCodecContext *avc,
+                            struct ws_intervals *inter)
+{
+    int i, edata_size = 4;
+    uint8_t *edata;
+
+    for (i = 0; i < inter->nb_inter; i++) {
+        edata_size += inter->inter[i].type == WS_SINE  ? 44 :
+                      inter->inter[i].type == WS_NOISE ? 32 : 0;
+        if (edata_size < 0)
+            return AVERROR(EOVERFLOW);
+    }
+    edata = av_malloc(edata_size);
+    if (!edata)
+        return AVERROR(ENOMEM);
+    avc->extradata = edata;
+    avc->extradata_size = edata_size;
+
+#define ADD_EDATA32(v) do { AV_WL32(edata, (v)); edata += 4; } while(0)
+#define ADD_EDATA64(v) do { AV_WL64(edata, (v)); edata += 8; } while(0)
+    ADD_EDATA32(inter->nb_inter);
+    for (i = 0; i < inter->nb_inter; i++) {
+        ADD_EDATA64(inter->inter[i].ts1);
+        ADD_EDATA64(inter->inter[i].ts2);
+        ADD_EDATA32(inter->inter[i].type);
+        ADD_EDATA32(inter->inter[i].channels);
+        switch (inter->inter[i].type) {
+            case WS_SINE:
+                ADD_EDATA32(inter->inter[i].f1);
+                ADD_EDATA32(inter->inter[i].f2);
+                ADD_EDATA32(inter->inter[i].a1);
+                ADD_EDATA32(inter->inter[i].a2);
+                ADD_EDATA32(inter->inter[i].phi);
+                break;
+            case WS_NOISE:
+                ADD_EDATA32(inter->inter[i].a1);
+                ADD_EDATA32(inter->inter[i].a2);
+                break;
+        }
+    }
+    if (edata != avc->extradata + edata_size)
+        return AVERROR_BUG;
+    return 0;
+}
+
+static av_cold int sbg_read_probe(AVProbeData *p)
+{
+    int r, score;
+    struct sbg_script script = { 0 };
+
+    r = parse_script(NULL, p->buf, p->buf_size, &script);
+    score = r < 0 || !script.nb_def || !script.nb_tseq ? 0 :
+            AVPROBE_SCORE_MAX / 3;
+    free_script(&script);
+    return score;
+}
+
+static av_cold int sbg_read_header(AVFormatContext *avf,
+                                   AVFormatParameters *ap)
+{
+    struct sbg_demuxer *sbg = avf->priv_data;
+    int r;
+    char *buf = NULL;
+    struct sbg_script script = { 0 };
+    AVStream *st;
+    struct ws_intervals inter = { 0 };
+
+    r = read_whole_file(avf->pb, sbg->max_file_size, &buf);
+    if (r < 0)
+        goto fail;
+    r = parse_script(avf, buf, r, &script);
+    if (r < 0)
+        goto fail;
+    if (!sbg->sample_rate)
+        sbg->sample_rate = script.sample_rate;
+    else
+        script.sample_rate = sbg->sample_rate;
+    if (!sbg->frame_size)
+        sbg->frame_size = FFMAX(1, sbg->sample_rate / 10);
+    if (script.opt_mix)
+        av_log(avf, AV_LOG_WARNING, "Mix feature not implemented: "
+               "-m is ignored and mix channels will be silent.\n");
+    r = expand_script(avf, &script);
+    if (r < 0)
+        goto fail;
+    av_freep(&buf);
+    r = generate_intervals(avf, &script, sbg->sample_rate, &inter);
+    if (r < 0)
+        goto fail;
+
+    st = avformat_new_stream(avf, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+    st->codec->codec_type     = AVMEDIA_TYPE_AUDIO;
+    st->codec->codec_id       = CODEC_ID_FFWAVESYNTH;
+    st->codec->channels       = 2;
+    st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
+    st->codec->sample_rate    = sbg->sample_rate;
+    st->codec->frame_size     = sbg->frame_size;
+    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+    st->probe_packets = 0;
+    st->start_time    = av_rescale(script.start_ts,
+                                   sbg->sample_rate, AV_TIME_BASE);
+    st->duration      = script.end_ts == AV_NOPTS_VALUE ? AV_NOPTS_VALUE :
+                        av_rescale(script.end_ts - script.start_ts,
+                                   sbg->sample_rate, AV_TIME_BASE);
+    st->cur_dts       = st->start_time;
+    r = encode_intervals(&script, st->codec, &inter);
+    if (r < 0)
+        goto fail;
+
+    av_free(inter.inter);
+    free_script(&script);
+    return 0;
+
+fail:
+    av_free(inter.inter);
+    free_script(&script);
+    av_free(buf);
+    return r;
+}
+
+static int sbg_read_packet(AVFormatContext *avf, AVPacket *packet)
+{
+    int64_t ts, end_ts;
+
+    ts = avf->streams[0]->cur_dts;
+    end_ts = ts + avf->streams[0]->codec->frame_size;
+    if (avf->streams[0]->duration != AV_NOPTS_VALUE)
+        end_ts = FFMIN(avf->streams[0]->start_time + avf->streams[0]->duration,
+                       end_ts);
+    if (end_ts <= ts)
+        return AVERROR_EOF;
+    if (av_new_packet(packet, 12) < 0)
+        return AVERROR(ENOMEM);
+    packet->dts = packet->pts = ts;
+    packet->duration = end_ts - ts;
+    AV_WL64(packet->data + 0, ts);
+    AV_WL32(packet->data + 8, packet->duration);
+    return packet->size;
+}
+
+static int sbg_read_seek2(AVFormatContext *avf, int stream_index,
+                          int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
+{
+    if (flags || stream_index > 0)
+        return AVERROR(ENOTSUP);
+    if (stream_index < 0)
+        ts = av_rescale_q(ts, AV_TIME_BASE_Q, avf->streams[0]->time_base);
+    avf->streams[0]->cur_dts = ts;
+    return 0;
+}
+
+#if FF_API_READ_SEEK
+static int sbg_read_seek(AVFormatContext *avf, int stream_index,
+                         int64_t ts, int flags)
+{
+    return sbg_read_seek2(avf, stream_index, ts, ts, ts, 0);
+}
+#endif
+
+static const AVOption sbg_options[] = {
+    { "sample_rate", "", offsetof(struct sbg_demuxer, sample_rate),
+      AV_OPT_TYPE_INT, { .dbl = 0 }, 0, INT_MAX,
+      AV_OPT_FLAG_DECODING_PARAM },
+    { "frame_size", "", offsetof(struct sbg_demuxer, frame_size),
+      AV_OPT_TYPE_INT, { .dbl = 0 }, 0, INT_MAX,
+      AV_OPT_FLAG_DECODING_PARAM },
+    { "max_file_size", "", offsetof(struct sbg_demuxer, max_file_size),
+      AV_OPT_TYPE_INT, { .dbl = 5000000 }, 0, INT_MAX,
+      AV_OPT_FLAG_DECODING_PARAM },
+    { NULL },
+};
+
+static const AVClass sbg_demuxer_class = {
+    .class_name = "sbg_demuxer",
+    .item_name  = av_default_item_name,
+    .option     = sbg_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_sbg_demuxer = {
+    .name           = "sbg",
+    .long_name      = NULL_IF_CONFIG_SMALL("SBaGen binaural beats script"),
+    .priv_data_size = sizeof(struct sbg_demuxer),
+    .read_probe     = sbg_read_probe,
+    .read_header    = sbg_read_header,
+    .read_packet    = sbg_read_packet,
+#if FF_API_READ_SEEK
+    .read_seek      = sbg_read_seek,
+#endif
+    .read_seek2     = sbg_read_seek2,
+    .extensions     = "sbg",
+    .priv_class     = &sbg_demuxer_class,
+};