summaryrefslogtreecommitdiffstats
path: root/libavformat/avc.c
blob: a041e843574845e29a125d99861fcf5b33ac26a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
/*
 * AVC helper functions for muxers
 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
 *
 * 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 "libavutil/intreadwrite.h"
#include "libavcodec/h264.h"
#include "libavcodec/get_bits.h"
#include "avformat.h"
#include "avio.h"
#include "avc.h"

static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
{
    const uint8_t *a = p + 4 - ((intptr_t)p & 3);

    for (end -= 3; p < a && p < end; p++) {
        if (p[0] == 0 && p[1] == 0 && p[2] == 1)
            return p;
    }

    for (end -= 3; p < end; p += 4) {
        uint32_t x = *(const uint32_t*)p;
//      if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
//      if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
        if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
            if (p[1] == 0) {
                if (p[0] == 0 && p[2] == 1)
                    return p;
                if (p[2] == 0 && p[3] == 1)
                    return p+1;
            }
            if (p[3] == 0) {
                if (p[2] == 0 && p[4] == 1)
                    return p+2;
                if (p[4] == 0 && p[5] == 1)
                    return p+3;
            }
        }
    }

    for (end += 3; p < end; p++) {
        if (p[0] == 0 && p[1] == 0 && p[2] == 1)
            return p;
    }

    return end + 3;
}

const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){
    const uint8_t *out= ff_avc_find_startcode_internal(p, end);
    if(p<out && out<end && !out[-1]) out--;
    return out;
}

int ff_avc_parse_nal_units(AVIOContext *pb, const uint8_t *buf_in, int size)
{
    const uint8_t *p = buf_in;
    const uint8_t *end = p + size;
    const uint8_t *nal_start, *nal_end;

    size = 0;
    nal_start = ff_avc_find_startcode(p, end);
    for (;;) {
        while (nal_start < end && !*(nal_start++));
        if (nal_start == end)
            break;

        nal_end = ff_avc_find_startcode(nal_start, end);
        avio_wb32(pb, nal_end - nal_start);
        avio_write(pb, nal_start, nal_end - nal_start);
        size += 4 + nal_end - nal_start;
        nal_start = nal_end;
    }
    return size;
}

int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
{
    AVIOContext *pb;
    int ret = avio_open_dyn_buf(&pb);
    if(ret < 0)
        return ret;

    ff_avc_parse_nal_units(pb, buf_in, *size);

    av_freep(buf);
    *size = avio_close_dyn_buf(pb, buf);
    return 0;
}

int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
{
    AVIOContext *sps_pb = NULL, *pps_pb = NULL;
    uint8_t *buf = NULL, *end, *start = NULL;
    uint8_t *sps = NULL, *pps = NULL;
    uint32_t sps_size = 0, pps_size = 0;
    int ret, nb_sps = 0, nb_pps = 0;

    if (len <= 6)
        return AVERROR_INVALIDDATA;

    /* check for H.264 start code */
    if (AV_RB32(data) != 0x00000001 &&
        AV_RB24(data) != 0x000001) {
        avio_write(pb, data, len);
        return 0;
    }

    ret = ff_avc_parse_nal_units_buf(data, &buf, &len);
    if (ret < 0)
        return ret;
    start = buf;
    end = buf + len;

    ret = avio_open_dyn_buf(&sps_pb);
    if (ret < 0)
        goto fail;
    ret = avio_open_dyn_buf(&pps_pb);
    if (ret < 0)
        goto fail;

    /* look for sps and pps */
    while (end - buf > 4) {
        uint32_t size;
        uint8_t nal_type;
        size = FFMIN(AV_RB32(buf), end - buf - 4);
        buf += 4;
        nal_type = buf[0] & 0x1f;

        if (nal_type == 7) { /* SPS */
            nb_sps++;
            if (size > UINT16_MAX || nb_sps >= H264_MAX_SPS_COUNT) {
                ret = AVERROR_INVALIDDATA;
                goto fail;
            }
            avio_wb16(sps_pb, size);
            avio_write(sps_pb, buf, size);
        } else if (nal_type == 8) { /* PPS */
            nb_pps++;
            if (size > UINT16_MAX || nb_pps >= H264_MAX_PPS_COUNT) {
                ret = AVERROR_INVALIDDATA;
                goto fail;
            }
            avio_wb16(pps_pb, size);
            avio_write(pps_pb, buf, size);
        }

        buf += size;
    }
    sps_size = avio_close_dyn_buf(sps_pb, &sps);
    pps_size = avio_close_dyn_buf(pps_pb, &pps);

    if (sps_size < 6 || !pps_size) {
        ret = AVERROR_INVALIDDATA;
        goto fail;
    }

    avio_w8(pb, 1); /* version */
    avio_w8(pb, sps[3]); /* profile */
    avio_w8(pb, sps[4]); /* profile compat */
    avio_w8(pb, sps[5]); /* level */
    avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
    avio_w8(pb, 0xe0 | nb_sps); /* 3 bits reserved (111) + 5 bits number of sps */

    avio_write(pb, sps, sps_size);
    avio_w8(pb, nb_pps); /* number of pps */
    avio_write(pb, pps, pps_size);

fail:
    if (!sps)
        avio_close_dyn_buf(sps_pb, &sps);
    if (!pps)
        avio_close_dyn_buf(pps_pb, &pps);
    av_free(sps);
    av_free(pps);
    av_free(start);

    return ret;
}

int ff_avc_write_annexb_extradata(const uint8_t *in, uint8_t **buf, int *size)
{
    uint16_t sps_size, pps_size;
    uint8_t *out;
    int out_size;

    *buf = NULL;
    if (*size >= 4 && (AV_RB32(in) == 0x00000001 || AV_RB24(in) == 0x000001))
        return 0;
    if (*size < 11 || in[0] != 1)
        return AVERROR_INVALIDDATA;

    sps_size = AV_RB16(&in[6]);
    if (11 + sps_size > *size)
        return AVERROR_INVALIDDATA;
    pps_size = AV_RB16(&in[9 + sps_size]);
    if (11 + sps_size + pps_size > *size)
        return AVERROR_INVALIDDATA;
    out_size = 8 + sps_size + pps_size;
    out = av_mallocz(out_size + AV_INPUT_BUFFER_PADDING_SIZE);
    if (!out)
        return AVERROR(ENOMEM);
    AV_WB32(&out[0], 0x00000001);
    memcpy(out + 4, &in[8], sps_size);
    AV_WB32(&out[4 + sps_size], 0x00000001);
    memcpy(out + 8 + sps_size, &in[11 + sps_size], pps_size);
    *buf = out;
    *size = out_size;
    return 0;
}

const uint8_t *ff_avc_mp4_find_startcode(const uint8_t *start,
                                         const uint8_t *end,
                                         int nal_length_size)
{
    unsigned int res = 0;

    if (end - start < nal_length_size)
        return NULL;
    while (nal_length_size--)
        res = (res << 8) | *start++;

    if (res > end - start)
        return NULL;

    return start + res;
}

uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len,
                                  uint32_t *dst_len, int header_len)
{
    uint8_t *dst;
    uint32_t i, len;

    dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE);
    if (!dst)
        return NULL;

    /* NAL unit header */
    i = len = 0;
    while (i < header_len && i < src_len)
        dst[len++] = src[i++];

    while (i + 2 < src_len)
        if (!src[i] && !src[i + 1] && src[i + 2] == 3) {
            dst[len++] = src[i++];
            dst[len++] = src[i++];
            i++; // remove emulation_prevention_three_byte
        } else
            dst[len++] = src[i++];

    while (i < src_len)
        dst[len++] = src[i++];

    memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);

    *dst_len = len;
    return dst;
}

static const AVRational avc_sample_aspect_ratio[17] = {
    {   0,  1 },
    {   1,  1 },
    {  12, 11 },
    {  10, 11 },
    {  16, 11 },
    {  40, 33 },
    {  24, 11 },
    {  20, 11 },
    {  32, 11 },
    {  80, 33 },
    {  18, 11 },
    {  15, 11 },
    {  64, 33 },
    { 160, 99 },
    {   4,  3 },
    {   3,  2 },
    {   2,  1 },
};

static inline int get_ue_golomb(GetBitContext *gb) {
    int i;
    for (i = 0; i < 32 && !get_bits1(gb); i++)
        ;
    return get_bitsz(gb, i) + (1 << i) - 1;
}

static inline int get_se_golomb(GetBitContext *gb) {
    int v = get_ue_golomb(gb) + 1;
    int sign = -(v & 1);
    return ((v >> 1) ^ sign) - sign;
}

H264SequenceParameterSet *ff_avc_decode_sps(const uint8_t *buf, int buf_size)
{
    int i, j, ret, rbsp_size, aspect_ratio_idc, pic_order_cnt_type;
    int num_ref_frames_in_pic_order_cnt_cycle;
    int delta_scale, lastScale = 8, nextScale = 8;
    int sizeOfScalingList;
    H264SequenceParameterSet *sps = NULL;
    GetBitContext gb;
    uint8_t *rbsp_buf;

    rbsp_buf = ff_nal_unit_extract_rbsp(buf, buf_size, &rbsp_size, 0);
    if (!rbsp_buf)
        return NULL;

    ret = init_get_bits8(&gb, rbsp_buf, rbsp_size);
    if (ret < 0)
        goto end;

    sps = av_mallocz(sizeof(*sps));
    if (!sps)
        goto end;

    sps->profile_idc = get_bits(&gb, 8);
    sps->constraint_set_flags |= get_bits1(&gb) << 0; // constraint_set0_flag
    sps->constraint_set_flags |= get_bits1(&gb) << 1; // constraint_set1_flag
    sps->constraint_set_flags |= get_bits1(&gb) << 2; // constraint_set2_flag
    sps->constraint_set_flags |= get_bits1(&gb) << 3; // constraint_set3_flag
    sps->constraint_set_flags |= get_bits1(&gb) << 4; // constraint_set4_flag
    sps->constraint_set_flags |= get_bits1(&gb) << 5; // constraint_set5_flag
    skip_bits(&gb, 2); // reserved_zero_2bits
    sps->level_idc = get_bits(&gb, 8);
    sps->id = get_ue_golomb(&gb);

    if (sps->profile_idc == 100 || sps->profile_idc == 110 ||
        sps->profile_idc == 122 || sps->profile_idc == 244 || sps->profile_idc ==  44 ||
        sps->profile_idc ==  83 || sps->profile_idc ==  86 || sps->profile_idc == 118 ||
        sps->profile_idc == 128 || sps->profile_idc == 138 || sps->profile_idc == 139 ||
        sps->profile_idc == 134) {
        sps->chroma_format_idc = get_ue_golomb(&gb); // chroma_format_idc
        if (sps->chroma_format_idc == 3) {
            skip_bits1(&gb); // separate_colour_plane_flag
        }
        sps->bit_depth_luma = get_ue_golomb(&gb) + 8;
        get_ue_golomb(&gb); // bit_depth_chroma_minus8
        skip_bits1(&gb); // qpprime_y_zero_transform_bypass_flag
        if (get_bits1(&gb)) { // seq_scaling_matrix_present_flag
            for (i = 0; i < ((sps->chroma_format_idc != 3) ? 8 : 12); i++) {
                if (!get_bits1(&gb)) // seq_scaling_list_present_flag
                    continue;
                lastScale = 8;
                nextScale = 8;
                sizeOfScalingList = i < 6 ? 16 : 64;
                for (j = 0; j < sizeOfScalingList; j++) {
                    if (nextScale != 0) {
                        delta_scale = get_se_golomb(&gb);
                        nextScale = (lastScale + delta_scale) & 0xff;
                    }
                    lastScale = nextScale == 0 ? lastScale : nextScale;
                }
            }
        }
    } else {
        sps->chroma_format_idc = 1;
        sps->bit_depth_luma = 8;
    }

    get_ue_golomb(&gb); // log2_max_frame_num_minus4
    pic_order_cnt_type = get_ue_golomb(&gb);

    if (pic_order_cnt_type == 0) {
        get_ue_golomb(&gb); // log2_max_pic_order_cnt_lsb_minus4
    } else if (pic_order_cnt_type == 1) {
        skip_bits1(&gb);    // delta_pic_order_always_zero
        get_se_golomb(&gb); // offset_for_non_ref_pic
        get_se_golomb(&gb); // offset_for_top_to_bottom_field
        num_ref_frames_in_pic_order_cnt_cycle = get_ue_golomb(&gb);
        for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++)
            get_se_golomb(&gb); // offset_for_ref_frame
    }

    get_ue_golomb(&gb); // max_num_ref_frames
    skip_bits1(&gb); // gaps_in_frame_num_value_allowed_flag
    get_ue_golomb(&gb); // pic_width_in_mbs_minus1
    get_ue_golomb(&gb); // pic_height_in_map_units_minus1

    sps->frame_mbs_only_flag = get_bits1(&gb);
    if (!sps->frame_mbs_only_flag)
        skip_bits1(&gb); // mb_adaptive_frame_field_flag

    skip_bits1(&gb); // direct_8x8_inference_flag

    if (get_bits1(&gb)) { // frame_cropping_flag
        get_ue_golomb(&gb); // frame_crop_left_offset
        get_ue_golomb(&gb); // frame_crop_right_offset
        get_ue_golomb(&gb); // frame_crop_top_offset
        get_ue_golomb(&gb); // frame_crop_bottom_offset
    }

    if (get_bits1(&gb)) { // vui_parameters_present_flag
        if (get_bits1(&gb)) { // aspect_ratio_info_present_flag
            aspect_ratio_idc = get_bits(&gb, 8);
            if (aspect_ratio_idc == 0xff) {
                sps->sar.num = get_bits(&gb, 16);
                sps->sar.den = get_bits(&gb, 16);
            } else if (aspect_ratio_idc < FF_ARRAY_ELEMS(avc_sample_aspect_ratio)) {
                sps->sar = avc_sample_aspect_ratio[aspect_ratio_idc];
            }
        }
    }

    if (!sps->sar.den) {
        sps->sar.num = 1;
        sps->sar.den = 1;
    }

 end:
    av_free(rbsp_buf);
    return sps;
}
OpenPOWER on IntegriCloud