d4a7f3193754c881bfca8920c9b97039a2c720a2
[libav.git] / libavcodec / h264_mp4toannexb_bsf.c
1 /*
2 * H.264 MP4 to Annex B byte stream format filter
3 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 #include "libavutil/intreadwrite.h"
23 #include "avcodec.h"
24
25 typedef struct H264BSFContext {
26 uint8_t length_size;
27 uint8_t first_idr;
28 int extradata_parsed;
29 } H264BSFContext;
30
31 static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size,
32 const uint8_t *sps_pps, uint32_t sps_pps_size,
33 const uint8_t *in, uint32_t in_size) {
34 uint32_t offset = *poutbuf_size;
35 uint8_t nal_header_size = offset ? 3 : 4;
36 void *tmp;
37
38 *poutbuf_size += sps_pps_size+in_size+nal_header_size;
39 tmp = av_realloc(*poutbuf, *poutbuf_size);
40 if (!tmp)
41 return AVERROR(ENOMEM);
42 *poutbuf = tmp;
43 if (sps_pps)
44 memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
45 memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
46 if (!offset) {
47 AV_WB32(*poutbuf+sps_pps_size, 1);
48 } else {
49 (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
50 (*poutbuf+offset+sps_pps_size)[2] = 1;
51 }
52
53 return 0;
54 }
55
56 static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
57 AVCodecContext *avctx, const char *args,
58 uint8_t **poutbuf, int *poutbuf_size,
59 const uint8_t *buf, int buf_size,
60 int keyframe) {
61 H264BSFContext *ctx = bsfc->priv_data;
62 uint8_t unit_type;
63 int32_t nal_size;
64 uint32_t cumul_size = 0;
65 const uint8_t *buf_end = buf + buf_size;
66
67 /* nothing to filter */
68 if (!avctx->extradata || avctx->extradata_size < 6) {
69 *poutbuf = (uint8_t*) buf;
70 *poutbuf_size = buf_size;
71 return 0;
72 }
73
74 /* retrieve sps and pps NAL units from extradata */
75 if (!ctx->extradata_parsed) {
76 uint16_t unit_size;
77 uint64_t total_size = 0;
78 uint8_t *out = NULL, unit_nb, sps_done = 0;
79 const uint8_t *extradata = avctx->extradata+4;
80 static const uint8_t nalu_header[4] = {0, 0, 0, 1};
81
82 /* retrieve length coded size */
83 ctx->length_size = (*extradata++ & 0x3) + 1;
84 if (ctx->length_size == 3)
85 return AVERROR(EINVAL);
86
87 /* retrieve sps and pps unit(s) */
88 unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
89 if (!unit_nb) {
90 unit_nb = *extradata++; /* number of pps unit(s) */
91 sps_done++;
92 }
93 while (unit_nb--) {
94 void *tmp;
95
96 unit_size = AV_RB16(extradata);
97 total_size += unit_size+4;
98 if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE ||
99 extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
100 av_free(out);
101 return AVERROR(EINVAL);
102 }
103 tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE);
104 if (!tmp) {
105 av_free(out);
106 return AVERROR(ENOMEM);
107 }
108 out = tmp;
109 memcpy(out+total_size-unit_size-4, nalu_header, 4);
110 memcpy(out+total_size-unit_size, extradata+2, unit_size);
111 extradata += 2+unit_size;
112
113 if (!unit_nb && !sps_done++)
114 unit_nb = *extradata++; /* number of pps unit(s) */
115 }
116
117 memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
118 av_free(avctx->extradata);
119 avctx->extradata = out;
120 avctx->extradata_size = total_size;
121 ctx->first_idr = 1;
122 ctx->extradata_parsed = 1;
123 }
124
125 *poutbuf_size = 0;
126 *poutbuf = NULL;
127 do {
128 if (buf + ctx->length_size > buf_end)
129 goto fail;
130
131 if (ctx->length_size == 1) {
132 nal_size = buf[0];
133 } else if (ctx->length_size == 2) {
134 nal_size = AV_RB16(buf);
135 } else
136 nal_size = AV_RB32(buf);
137
138 buf += ctx->length_size;
139 unit_type = *buf & 0x1f;
140
141 if (buf + nal_size > buf_end || nal_size < 0)
142 goto fail;
143
144 /* prepend only to the first type 5 NAL unit of an IDR picture */
145 if (ctx->first_idr && unit_type == 5) {
146 if (alloc_and_copy(poutbuf, poutbuf_size,
147 avctx->extradata, avctx->extradata_size,
148 buf, nal_size) < 0)
149 goto fail;
150 ctx->first_idr = 0;
151 } else {
152 if (alloc_and_copy(poutbuf, poutbuf_size,
153 NULL, 0,
154 buf, nal_size) < 0)
155 goto fail;
156 if (!ctx->first_idr && unit_type == 1)
157 ctx->first_idr = 1;
158 }
159
160 buf += nal_size;
161 cumul_size += nal_size + ctx->length_size;
162 } while (cumul_size < buf_size);
163
164 return 1;
165
166 fail:
167 av_freep(poutbuf);
168 *poutbuf_size = 0;
169 return AVERROR(EINVAL);
170 }
171
172 AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
173 "h264_mp4toannexb",
174 sizeof(H264BSFContext),
175 h264_mp4toannexb_filter,
176 };
177