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
24 #include "libavutil/avassert.h"
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/mem.h"
32 typedef struct H264BSFContext {
42 static int alloc_and_copy(AVPacket *out,
43 const uint8_t *sps_pps, uint32_t sps_pps_size,
44 const uint8_t *in, uint32_t in_size, int ps)
46 uint32_t offset = out->size;
47 uint8_t start_code_size = offset == 0 || ps ? 4 : 3;
50 err = av_grow_packet(out, sps_pps_size + in_size + start_code_size);
55 memcpy(out->data + offset, sps_pps, sps_pps_size);
56 memcpy(out->data + sps_pps_size + start_code_size + offset, in, in_size);
57 if (start_code_size == 4) {
58 AV_WB32(out->data + offset + sps_pps_size, 1);
60 (out->data + offset + sps_pps_size)[0] =
61 (out->data + offset + sps_pps_size)[1] = 0;
62 (out->data + offset + sps_pps_size)[2] = 1;
68 static int h264_extradata_to_annexb(AVBSFContext *ctx, const int padding)
70 H264BSFContext *s = ctx->priv_data;
72 uint32_t total_size = 0;
73 uint8_t *out = NULL, unit_nb, sps_done = 0,
74 sps_seen = 0, pps_seen = 0;
75 const uint8_t *extradata = ctx->par_in->extradata + 4;
76 static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
77 int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size
79 s->sps_offset = s->pps_offset = -1;
81 /* retrieve sps and pps unit(s) */
82 unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
93 unit_size = AV_RB16(extradata);
94 total_size += unit_size + 4;
95 av_assert1(total_size <= INT_MAX - padding);
96 if (extradata + 2 + unit_size > ctx->par_in->extradata + ctx->par_in->extradata_size) {
97 av_log(ctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, "
98 "corrupted stream or invalid MP4/AVCC bitstream\n");
100 return AVERROR(EINVAL);
102 if ((err = av_reallocp(&out, total_size + padding)) < 0)
104 memcpy(out + total_size - unit_size - 4, nalu_header, 4);
105 memcpy(out + total_size - unit_size, extradata + 2, unit_size);
106 extradata += 2 + unit_size;
108 if (!unit_nb && !sps_done++) {
109 unit_nb = *extradata++; /* number of pps unit(s) */
111 s->pps_offset = total_size;
118 memset(out + total_size, 0, padding);
121 av_log(ctx, AV_LOG_WARNING,
122 "Warning: SPS NALU missing or invalid. "
123 "The resulting stream may not play.\n");
126 av_log(ctx, AV_LOG_WARNING,
127 "Warning: PPS NALU missing or invalid. "
128 "The resulting stream may not play.\n");
130 av_freep(&ctx->par_out->extradata);
131 ctx->par_out->extradata = out;
132 ctx->par_out->extradata_size = total_size;
137 static int h264_mp4toannexb_init(AVBSFContext *ctx)
139 H264BSFContext *s = ctx->priv_data;
140 int extra_size = ctx->par_in->extradata_size;
143 /* retrieve sps and pps NAL units from extradata */
145 (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) ||
146 (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) {
147 av_log(ctx, AV_LOG_VERBOSE,
148 "The input looks like it is Annex B already\n");
149 } else if (extra_size >= 6) {
150 ret = h264_extradata_to_annexb(ctx, AV_INPUT_BUFFER_PADDING_SIZE);
154 s->length_size = ret;
158 s->extradata_parsed = 1;
160 av_log(ctx, AV_LOG_ERROR, "Invalid extradata size: %d\n", extra_size);
161 return AVERROR_INVALIDDATA;
167 static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
169 H264BSFContext *s = ctx->priv_data;
174 uint32_t cumul_size = 0;
176 const uint8_t *buf_end;
180 ret = ff_bsf_get_packet(ctx, &in);
184 /* nothing to filter */
185 if (!s->extradata_parsed) {
186 av_packet_move_ref(out, in);
193 buf_end = in->data + in->size;
196 ret= AVERROR(EINVAL);
197 if (buf + s->length_size > buf_end)
200 for (nal_size = 0, i = 0; i<s->length_size; i++)
201 nal_size = (nal_size << 8) | buf[i];
203 buf += s->length_size;
204 unit_type = *buf & 0x1f;
206 if (nal_size > buf_end - buf || nal_size < 0)
209 if (unit_type == H264_NAL_SPS)
210 s->idr_sps_seen = s->new_idr = 1;
211 else if (unit_type == H264_NAL_PPS) {
212 s->idr_pps_seen = s->new_idr = 1;
213 /* if SPS has not been seen yet, prepend the AVCC one to PPS */
214 if (!s->idr_sps_seen) {
215 if (s->sps_offset == -1)
216 av_log(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
218 if ((ret = alloc_and_copy(out,
219 ctx->par_out->extradata + s->sps_offset,
220 s->pps_offset != -1 ? s->pps_offset : ctx->par_out->extradata_size - s->sps_offset,
221 buf, nal_size, 1)) < 0)
229 /* if this is a new IDR picture following an IDR picture, reset the idr flag.
230 * Just check first_mb_in_slice to be 0 as this is the simplest solution.
231 * This could be checking idr_pic_id instead, but would complexify the parsing. */
232 if (!s->new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
235 /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
236 if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && !s->idr_sps_seen && !s->idr_pps_seen) {
237 if ((ret=alloc_and_copy(out,
238 ctx->par_out->extradata, ctx->par_out->extradata_size,
239 buf, nal_size, 1)) < 0)
242 /* if only SPS has been seen, also insert PPS */
243 } else if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && s->idr_sps_seen && !s->idr_pps_seen) {
244 if (s->pps_offset == -1) {
245 av_log(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
246 if ((ret = alloc_and_copy(out, NULL, 0, buf, nal_size, 0)) < 0)
248 } else if ((ret = alloc_and_copy(out,
249 ctx->par_out->extradata + s->pps_offset, ctx->par_out->extradata_size - s->pps_offset,
250 buf, nal_size, 1)) < 0)
253 if ((ret=alloc_and_copy(out, NULL, 0, buf, nal_size, unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)) < 0)
255 if (!s->new_idr && unit_type == H264_NAL_SLICE) {
264 cumul_size += nal_size + s->length_size;
265 } while (cumul_size < buf_size);
267 ret = av_packet_copy_props(out, in);
273 av_packet_unref(out);
279 static void h264_mp4toannexb_flush(AVBSFContext *ctx)
281 H264BSFContext *s = ctx->priv_data;
285 s->new_idr = s->extradata_parsed;
288 static const enum AVCodecID codec_ids[] = {
289 AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
292 const AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
293 .name = "h264_mp4toannexb",
294 .priv_data_size = sizeof(H264BSFContext),
295 .init = h264_mp4toannexb_init,
296 .filter = h264_mp4toannexb_filter,
297 .flush = h264_mp4toannexb_flush,
298 .codec_ids = codec_ids,