2 * H.264 MP4 to Annex B byte stream format filter
3 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/intreadwrite.h"
25 typedef struct H264BSFContext {
28 uint8_t *sps_pps_data;
32 static void alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size,
33 const uint8_t *sps_pps, uint32_t sps_pps_size,
34 const uint8_t *in, uint32_t in_size) {
35 uint32_t offset = *poutbuf_size;
36 uint8_t nal_header_size = offset ? 3 : 4;
38 *poutbuf_size += sps_pps_size+in_size+nal_header_size;
39 *poutbuf = av_realloc(*poutbuf, *poutbuf_size);
41 memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
42 memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
44 AV_WB32(*poutbuf+sps_pps_size, 1);
46 (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
47 (*poutbuf+offset+sps_pps_size)[2] = 1;
51 static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
52 AVCodecContext *avctx, const char *args,
53 uint8_t **poutbuf, int *poutbuf_size,
54 const uint8_t *buf, int buf_size,
56 H264BSFContext *ctx = bsfc->priv_data;
59 uint32_t cumul_size = 0;
60 const uint8_t *buf_end = buf + buf_size;
62 /* nothing to filter */
63 if (!avctx->extradata || avctx->extradata_size < 6) {
64 *poutbuf = (uint8_t*) buf;
65 *poutbuf_size = buf_size;
69 /* retrieve sps and pps NAL units from extradata */
70 if (!ctx->sps_pps_data) {
72 uint32_t total_size = 0;
73 uint8_t *out = NULL, unit_nb, sps_done = 0;
74 const uint8_t *extradata = avctx->extradata+4;
75 static const uint8_t nalu_header[4] = {0, 0, 0, 1};
77 /* retrieve length coded size */
78 ctx->length_size = (*extradata++ & 0x3) + 1;
79 if (ctx->length_size == 3)
80 return AVERROR(EINVAL);
82 /* retrieve sps and pps unit(s) */
83 unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
85 unit_nb = *extradata++; /* number of pps unit(s) */
89 unit_size = AV_RB16(extradata);
90 total_size += unit_size+4;
91 if (extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
93 return AVERROR(EINVAL);
95 out = av_realloc(out, total_size);
97 return AVERROR(ENOMEM);
98 memcpy(out+total_size-unit_size-4, nalu_header, 4);
99 memcpy(out+total_size-unit_size, extradata+2, unit_size);
100 extradata += 2+unit_size;
102 if (!unit_nb && !sps_done++)
103 unit_nb = *extradata++; /* number of pps unit(s) */
106 ctx->sps_pps_data = out;
107 ctx->size = total_size;
114 if (buf + ctx->length_size > buf_end)
117 if (ctx->length_size == 1)
119 else if (ctx->length_size == 2)
120 nal_size = AV_RB16(buf);
122 nal_size = AV_RB32(buf);
124 buf += ctx->length_size;
125 unit_type = *buf & 0x1f;
127 if (buf + nal_size > buf_end || nal_size < 0)
130 /* prepend only to the first type 5 NAL unit of an IDR picture */
131 if (ctx->first_idr && unit_type == 5) {
132 alloc_and_copy(poutbuf, poutbuf_size,
133 ctx->sps_pps_data, ctx->size,
138 alloc_and_copy(poutbuf, poutbuf_size,
141 if (!ctx->first_idr && unit_type == 1)
146 cumul_size += nal_size + ctx->length_size;
147 } while (cumul_size < buf_size);
154 return AVERROR(EINVAL);
157 static void h264_mp4toannexb_close(AVBitStreamFilterContext *bsfc)
159 H264BSFContext *ctx = bsfc->priv_data;
160 av_freep(&ctx->sps_pps_data);
163 AVBitStreamFilter h264_mp4toannexb_bsf = {
165 sizeof(H264BSFContext),
166 h264_mp4toannexb_filter,
167 h264_mp4toannexb_close,