diff options
Diffstat (limited to 'libavfilter/af_astreamsync.c')
| -rw-r--r-- | libavfilter/af_astreamsync.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/libavfilter/af_astreamsync.c b/libavfilter/af_astreamsync.c new file mode 100644 index 0000000..ccf55c0 --- /dev/null +++ b/libavfilter/af_astreamsync.c @@ -0,0 +1,208 @@ +/* + * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org> + * + * 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 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 + */ + +/** + * @file + * Stream (de)synchronization filter + */ + +#include "libavutil/eval.h" +#include "avfilter.h" +#include "internal.h" + +#define QUEUE_SIZE 16 + +static const char * const var_names[] = { + "b1", "b2", + "s1", "s2", + "t1", "t2", + NULL +}; + +enum var_name { + VAR_B1, VAR_B2, + VAR_S1, VAR_S2, + VAR_T1, VAR_T2, + VAR_NB +}; + +typedef struct { + AVExpr *expr; + double var_values[VAR_NB]; + struct buf_queue { + AVFilterBufferRef *buf[QUEUE_SIZE]; + unsigned tail, nb; + /* buf[tail] is the oldest, + buf[(tail + nb) % QUEUE_SIZE] is where the next is added */ + } queue[2]; + int req[2]; + int next_out; + int eof; /* bitmask, one bit for each stream */ +} AStreamSyncContext; + +static const char *default_expr = "t1-t2"; + +static av_cold int init(AVFilterContext *ctx, const char *args0, void *opaque) +{ + AStreamSyncContext *as = ctx->priv; + const char *expr = args0 ? args0 : default_expr; + int r, i; + + r = av_expr_parse(&as->expr, expr, var_names, + NULL, NULL, NULL, NULL, 0, ctx); + if (r < 0) { + av_log(ctx, AV_LOG_ERROR, "Error in expression \"%s\"\n", expr); + return r; + } + for (i = 0; i < 42; i++) + av_expr_eval(as->expr, as->var_values, NULL); /* exercize prng */ + return 0; +} + +static int query_formats(AVFilterContext *ctx) +{ + int i; + AVFilterFormats *formats; + + for (i = 0; i < 2; i++) { + formats = ctx->inputs[i]->in_formats; + avfilter_formats_ref(formats, &ctx->inputs[i]->out_formats); + avfilter_formats_ref(formats, &ctx->outputs[i]->in_formats); + formats = ctx->inputs[i]->in_packing; + avfilter_formats_ref(formats, &ctx->inputs[i]->out_packing); + avfilter_formats_ref(formats, &ctx->outputs[i]->in_packing); + formats = ctx->inputs[i]->in_chlayouts; + avfilter_formats_ref(formats, &ctx->inputs[i]->out_chlayouts); + avfilter_formats_ref(formats, &ctx->outputs[i]->in_chlayouts); + } + return 0; +} + +static int config_output(AVFilterLink *outlink) +{ + AVFilterContext *ctx = outlink->src; + int id = outlink == ctx->outputs[1]; + + outlink->sample_rate = ctx->inputs[id]->sample_rate; + outlink->time_base = ctx->inputs[id]->time_base; + return 0; +} + +static void send_out(AVFilterContext *ctx, int out_id) +{ + AStreamSyncContext *as = ctx->priv; + struct buf_queue *queue = &as->queue[out_id]; + AVFilterBufferRef *buf = queue->buf[queue->tail]; + + queue->buf[queue->tail] = NULL; + as->var_values[VAR_B1 + out_id]++; + as->var_values[VAR_S1 + out_id] += buf->audio->nb_samples; + if (buf->pts != AV_NOPTS_VALUE) + as->var_values[VAR_T1 + out_id] = + av_q2d(ctx->outputs[out_id]->time_base) * buf->pts; + as->var_values[VAR_T1 + out_id] += buf->audio->nb_samples / + (double)ctx->inputs[out_id]->sample_rate; + avfilter_filter_samples(ctx->outputs[out_id], buf); + queue->nb--; + queue->tail = (queue->tail + 1) % QUEUE_SIZE; + if (as->req[out_id]) + as->req[out_id]--; +} + +static void send_next(AVFilterContext *ctx) +{ + AStreamSyncContext *as = ctx->priv; + int i; + + while (1) { + if (!as->queue[as->next_out].nb) + break; + send_out(ctx, as->next_out); + if (!as->eof) + as->next_out = av_expr_eval(as->expr, as->var_values, NULL) >= 0; + } + for (i = 0; i < 2; i++) + if (as->queue[i].nb == QUEUE_SIZE) + send_out(ctx, i); +} + +static int request_frame(AVFilterLink *outlink) +{ + AVFilterContext *ctx = outlink->src; + AStreamSyncContext *as = ctx->priv; + int id = outlink == ctx->outputs[1]; + + as->req[id]++; + while (as->req[id] && !(as->eof & (1 << id))) { + if (as->queue[as->next_out].nb) { + send_next(ctx); + } else { + as->eof |= 1 << as->next_out; + avfilter_request_frame(ctx->inputs[as->next_out]); + if (as->eof & (1 << as->next_out)) + as->next_out = !as->next_out; + } + } + return 0; +} + +static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) +{ + AVFilterContext *ctx = inlink->dst; + AStreamSyncContext *as = ctx->priv; + int id = inlink == ctx->inputs[1]; + + as->queue[id].buf[(as->queue[id].tail + as->queue[id].nb++) % QUEUE_SIZE] = + insamples; + as->eof &= ~(1 << id); + send_next(ctx); +} + +AVFilter avfilter_af_astreamsync = { + .name = "astreamsync", + .description = NULL_IF_CONFIG_SMALL("Copy two streams of audio data " + "in a configurable order."), + .priv_size = sizeof(AStreamSyncContext), + .init = init, + .query_formats = query_formats, + + .inputs = (const AVFilterPad[]) { + { .name = "in1", + .type = AVMEDIA_TYPE_AUDIO, + .filter_samples = filter_samples, + .min_perms = AV_PERM_READ, }, + { .name = "in2", + .type = AVMEDIA_TYPE_AUDIO, + .filter_samples = filter_samples, + .min_perms = AV_PERM_READ, }, + { .name = NULL } + }, + .outputs = (const AVFilterPad[]) { + { .name = "out1", + .type = AVMEDIA_TYPE_AUDIO, + .config_props = config_output, + .request_frame = request_frame, }, + { .name = "out2", + .type = AVMEDIA_TYPE_AUDIO, + .config_props = config_output, + .request_frame = request_frame, }, + { .name = NULL } + }, +}; |
