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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 <string.h> | |
23 | ||
24 | #include "libavutil/intreadwrite.h" | |
25 | #include "libavutil/mem.h" | |
26 | #include "avcodec.h" | |
27 | ||
28 | typedef struct H264BSFContext { | |
29 | uint8_t length_size; | |
30 | uint8_t new_idr; | |
31 | uint8_t idr_sps_pps_seen; | |
32 | int extradata_parsed; | |
33 | } H264BSFContext; | |
34 | ||
35 | static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size, | |
36 | const uint8_t *sps_pps, uint32_t sps_pps_size, | |
37 | const uint8_t *in, uint32_t in_size) | |
38 | { | |
39 | uint32_t offset = *poutbuf_size; | |
40 | uint8_t nal_header_size = offset ? 3 : 4; | |
41 | int err; | |
42 | ||
43 | *poutbuf_size += sps_pps_size + in_size + nal_header_size; | |
44 | if ((err = av_reallocp(poutbuf, | |
45 | *poutbuf_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0) { | |
46 | *poutbuf_size = 0; | |
47 | return err; | |
48 | } | |
49 | if (sps_pps) | |
50 | memcpy(*poutbuf + offset, sps_pps, sps_pps_size); | |
51 | memcpy(*poutbuf + sps_pps_size + nal_header_size + offset, in, in_size); | |
52 | if (!offset) { | |
53 | AV_WB32(*poutbuf + sps_pps_size, 1); | |
54 | } else { | |
55 | (*poutbuf + offset + sps_pps_size)[0] = | |
56 | (*poutbuf + offset + sps_pps_size)[1] = 0; | |
57 | (*poutbuf + offset + sps_pps_size)[2] = 1; | |
58 | } | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | static int h264_extradata_to_annexb(AVCodecContext *avctx, const int padding) | |
64 | { | |
65 | uint16_t unit_size; | |
66 | uint64_t total_size = 0; | |
67 | uint8_t *out = NULL, unit_nb, sps_done = 0, | |
68 | sps_seen = 0, pps_seen = 0; | |
69 | const uint8_t *extradata = avctx->extradata + 4; | |
70 | static const uint8_t nalu_header[4] = { 0, 0, 0, 1 }; | |
71 | int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size | |
72 | ||
73 | /* retrieve sps and pps unit(s) */ | |
74 | unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */ | |
75 | if (!unit_nb) { | |
76 | goto pps; | |
77 | } else { | |
78 | sps_seen = 1; | |
79 | } | |
80 | ||
81 | while (unit_nb--) { | |
82 | int err; | |
83 | ||
84 | unit_size = AV_RB16(extradata); | |
85 | total_size += unit_size + 4; | |
86 | if (total_size > INT_MAX - padding) { | |
87 | av_log(avctx, AV_LOG_ERROR, | |
88 | "Too big extradata size, corrupted stream or invalid MP4/AVCC bitstream\n"); | |
89 | av_free(out); | |
90 | return AVERROR(EINVAL); | |
91 | } | |
92 | if (extradata + 2 + unit_size > avctx->extradata + avctx->extradata_size) { | |
93 | av_log(avctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, " | |
94 | "corrupted stream or invalid MP4/AVCC bitstream\n"); | |
95 | av_free(out); | |
96 | return AVERROR(EINVAL); | |
97 | } | |
98 | if ((err = av_reallocp(&out, total_size + padding)) < 0) | |
99 | return err; | |
100 | memcpy(out + total_size - unit_size - 4, nalu_header, 4); | |
101 | memcpy(out + total_size - unit_size, extradata + 2, unit_size); | |
102 | extradata += 2 + unit_size; | |
103 | pps: | |
104 | if (!unit_nb && !sps_done++) { | |
105 | unit_nb = *extradata++; /* number of pps unit(s) */ | |
106 | if (unit_nb) | |
107 | pps_seen = 1; | |
108 | } | |
109 | } | |
110 | ||
111 | if (out) | |
112 | memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE); | |
113 | ||
114 | if (!sps_seen) | |
115 | av_log(avctx, AV_LOG_WARNING, | |
116 | "Warning: SPS NALU missing or invalid. " | |
117 | "The resulting stream may not play.\n"); | |
118 | ||
119 | if (!pps_seen) | |
120 | av_log(avctx, AV_LOG_WARNING, | |
121 | "Warning: PPS NALU missing or invalid. " | |
122 | "The resulting stream may not play.\n"); | |
123 | ||
124 | av_free(avctx->extradata); | |
125 | avctx->extradata = out; | |
126 | avctx->extradata_size = total_size; | |
127 | ||
128 | return length_size; | |
129 | } | |
130 | ||
131 | static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc, | |
132 | AVCodecContext *avctx, const char *args, | |
133 | uint8_t **poutbuf, int *poutbuf_size, | |
134 | const uint8_t *buf, int buf_size, | |
135 | int keyframe) | |
136 | { | |
137 | H264BSFContext *ctx = bsfc->priv_data; | |
138 | int i; | |
139 | uint8_t unit_type; | |
140 | int32_t nal_size; | |
141 | uint32_t cumul_size = 0; | |
142 | const uint8_t *buf_end = buf + buf_size; | |
143 | int ret = 0; | |
144 | ||
145 | /* nothing to filter */ | |
146 | if (!avctx->extradata || avctx->extradata_size < 6) { | |
147 | *poutbuf = (uint8_t *)buf; | |
148 | *poutbuf_size = buf_size; | |
149 | return 0; | |
150 | } | |
151 | ||
152 | /* retrieve sps and pps NAL units from extradata */ | |
153 | if (!ctx->extradata_parsed) { | |
154 | ret = h264_extradata_to_annexb(avctx, FF_INPUT_BUFFER_PADDING_SIZE); | |
155 | if (ret < 0) | |
156 | return ret; | |
157 | ctx->length_size = ret; | |
158 | ctx->new_idr = 1; | |
159 | ctx->idr_sps_pps_seen = 0; | |
160 | ctx->extradata_parsed = 1; | |
161 | } | |
162 | ||
163 | *poutbuf_size = 0; | |
164 | *poutbuf = NULL; | |
165 | do { | |
166 | ret= AVERROR(EINVAL); | |
167 | if (buf + ctx->length_size > buf_end) | |
168 | goto fail; | |
169 | ||
170 | for (nal_size = 0, i = 0; i<ctx->length_size; i++) | |
171 | nal_size = (nal_size << 8) | buf[i]; | |
172 | ||
173 | buf += ctx->length_size; | |
174 | unit_type = *buf & 0x1f; | |
175 | ||
176 | if (buf + nal_size > buf_end || nal_size < 0) | |
177 | goto fail; | |
178 | ||
179 | if (unit_type == 7 || unit_type == 8) | |
180 | ctx->idr_sps_pps_seen = 1; | |
181 | ||
182 | /* if this is a new IDR picture following an IDR picture, reset the idr flag. | |
183 | * Just check first_mb_in_slice to be 0 as this is the simplest solution. | |
184 | * This could be checking idr_pic_id instead, but would complexify the parsing. */ | |
185 | if (!ctx->new_idr && unit_type == 5 && (buf[1] & 0x80)) | |
186 | ctx->new_idr = 1; | |
187 | ||
188 | /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */ | |
189 | if (ctx->new_idr && unit_type == 5 && !ctx->idr_sps_pps_seen) { | |
190 | if ((ret=alloc_and_copy(poutbuf, poutbuf_size, | |
191 | avctx->extradata, avctx->extradata_size, | |
192 | buf, nal_size)) < 0) | |
193 | goto fail; | |
194 | ctx->new_idr = 0; | |
195 | } else { | |
196 | if ((ret=alloc_and_copy(poutbuf, poutbuf_size, | |
197 | NULL, 0, buf, nal_size)) < 0) | |
198 | goto fail; | |
199 | if (!ctx->new_idr && unit_type == 1) { | |
200 | ctx->new_idr = 1; | |
201 | ctx->idr_sps_pps_seen = 0; | |
202 | } | |
203 | } | |
204 | ||
205 | buf += nal_size; | |
206 | cumul_size += nal_size + ctx->length_size; | |
207 | } while (cumul_size < buf_size); | |
208 | ||
209 | return 1; | |
210 | ||
211 | fail: | |
212 | av_freep(poutbuf); | |
213 | *poutbuf_size = 0; | |
214 | return ret; | |
215 | } | |
216 | ||
217 | AVBitStreamFilter ff_h264_mp4toannexb_bsf = { | |
218 | .name = "h264_mp4toannexb", | |
219 | .priv_data_size = sizeof(H264BSFContext), | |
220 | .filter = h264_mp4toannexb_filter, | |
221 | }; |