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/intreadwrite.h"
25 #include "libavutil/mem.h"
31 typedef struct H264BSFContext {
41 static int alloc_and_copy(AVPacket *out,
42 const uint8_t *sps_pps, uint32_t sps_pps_size,
43 const uint8_t *in, uint32_t in_size, int ps)
45 uint32_t offset = out->size;
46 uint8_t start_code_size = offset == 0 || ps ? 4 : 3;
49 err = av_grow_packet(out, sps_pps_size + in_size + start_code_size);
54 memcpy(out->data + offset, sps_pps, sps_pps_size);
55 memcpy(out->data + sps_pps_size + start_code_size + offset, in, in_size);
56 if (start_code_size == 4) {
57 AV_WB32(out->data + offset + sps_pps_size, 1);
59 (out->data + offset + sps_pps_size)[0] =
60 (out->data + offset + sps_pps_size)[1] = 0;
61 (out->data + offset + sps_pps_size)[2] = 1;
67 static int h264_extradata_to_annexb(AVBSFContext *ctx, const int padding)
69 H264BSFContext *s = ctx->priv_data;
71 uint64_t total_size = 0;
72 uint8_t *out = NULL, unit_nb, sps_done = 0,
73 sps_seen = 0, pps_seen = 0;
74 const uint8_t *extradata = ctx->par_in->extradata + 4;
75 static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
76 int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size
78 s->sps_offset = s->pps_offset = -1;
80 /* retrieve sps and pps unit(s) */
81 unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
92 unit_size = AV_RB16(extradata);
93 total_size += unit_size + 4;
94 if (total_size > INT_MAX - padding) {
95 av_log(ctx, AV_LOG_ERROR,
96 "Too big extradata size, corrupted stream or invalid MP4/AVCC bitstream\n");
98 return AVERROR(EINVAL);
100 if (extradata + 2 + unit_size > ctx->par_in->extradata + ctx->par_in->extradata_size) {
101 av_log(ctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, "
102 "corrupted stream or invalid MP4/AVCC bitstream\n");
104 return AVERROR(EINVAL);
106 if ((err = av_reallocp(&out, total_size + padding)) < 0)
108 memcpy(out + total_size - unit_size - 4, nalu_header, 4);
109 memcpy(out + total_size - unit_size, extradata + 2, unit_size);
110 extradata += 2 + unit_size;
112 if (!unit_nb && !sps_done++) {
113 unit_nb = *extradata++; /* number of pps unit(s) */
115 s->pps_offset = total_size;
122 memset(out + total_size, 0, padding);
125 av_log(ctx, AV_LOG_WARNING,
126 "Warning: SPS NALU missing or invalid. "
127 "The resulting stream may not play.\n");
130 av_log(ctx, AV_LOG_WARNING,
131 "Warning: PPS NALU missing or invalid. "
132 "The resulting stream may not play.\n");
134 av_freep(&ctx->par_out->extradata);
135 ctx->par_out->extradata = out;
136 ctx->par_out->extradata_size = total_size;
141 static int h264_mp4toannexb_init(AVBSFContext *ctx)
143 H264BSFContext *s = ctx->priv_data;
144 int extra_size = ctx->par_in->extradata_size;
147 /* retrieve sps and pps NAL units from extradata */
149 (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) ||
150 (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) {
151 av_log(ctx, AV_LOG_VERBOSE,
152 "The input looks like it is Annex B already\n");
153 } else if (extra_size >= 6) {
154 ret = h264_extradata_to_annexb(ctx, AV_INPUT_BUFFER_PADDING_SIZE);
158 s->length_size = ret;
162 s->extradata_parsed = 1;
164 av_log(ctx, AV_LOG_ERROR, "Invalid extradata size: %d\n", extra_size);
165 return AVERROR_INVALIDDATA;
171 static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
173 H264BSFContext *s = ctx->priv_data;
178 uint32_t cumul_size = 0;
180 const uint8_t *buf_end;
184 ret = ff_bsf_get_packet(ctx, &in);
188 /* nothing to filter */
189 if (!s->extradata_parsed) {
190 av_packet_move_ref(out, in);
197 buf_end = in->data + in->size;
200 ret= AVERROR(EINVAL);
201 if (buf + s->length_size > buf_end)
204 for (nal_size = 0, i = 0; i<s->length_size; i++)
205 nal_size = (nal_size << 8) | buf[i];
207 buf += s->length_size;
208 unit_type = *buf & 0x1f;
210 if (nal_size > buf_end - buf || nal_size < 0)
213 if (unit_type == H264_NAL_SPS)
214 s->idr_sps_seen = s->new_idr = 1;
215 else if (unit_type == H264_NAL_PPS) {
216 s->idr_pps_seen = s->new_idr = 1;
217 /* if SPS has not been seen yet, prepend the AVCC one to PPS */
218 if (!s->idr_sps_seen) {
219 if (s->sps_offset == -1)
220 av_log(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
222 if ((ret = alloc_and_copy(out,
223 ctx->par_out->extradata + s->sps_offset,
224 s->pps_offset != -1 ? s->pps_offset : ctx->par_out->extradata_size - s->sps_offset,
225 buf, nal_size, 1)) < 0)
233 /* if this is a new IDR picture following an IDR picture, reset the idr flag.
234 * Just check first_mb_in_slice to be 0 as this is the simplest solution.
235 * This could be checking idr_pic_id instead, but would complexify the parsing. */
236 if (!s->new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
239 /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
240 if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && !s->idr_sps_seen && !s->idr_pps_seen) {
241 if ((ret=alloc_and_copy(out,
242 ctx->par_out->extradata, ctx->par_out->extradata_size,
243 buf, nal_size, 1)) < 0)
246 /* if only SPS has been seen, also insert PPS */
247 } else if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && s->idr_sps_seen && !s->idr_pps_seen) {
248 if (s->pps_offset == -1) {
249 av_log(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
250 if ((ret = alloc_and_copy(out, NULL, 0, buf, nal_size, 0)) < 0)
252 } else if ((ret = alloc_and_copy(out,
253 ctx->par_out->extradata + s->pps_offset, ctx->par_out->extradata_size - s->pps_offset,
254 buf, nal_size, 1)) < 0)
257 if ((ret=alloc_and_copy(out, NULL, 0, buf, nal_size, unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)) < 0)
259 if (!s->new_idr && unit_type == H264_NAL_SLICE) {
268 cumul_size += nal_size + s->length_size;
269 } while (cumul_size < buf_size);
271 ret = av_packet_copy_props(out, in);
277 av_packet_unref(out);
283 static void h264_mp4toannexb_flush(AVBSFContext *ctx)
285 H264BSFContext *s = ctx->priv_data;
289 s->new_idr = s->extradata_parsed;
292 static const enum AVCodecID codec_ids[] = {
293 AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
296 const AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
297 .name = "h264_mp4toannexb",
298 .priv_data_size = sizeof(H264BSFContext),
299 .init = h264_mp4toannexb_init,
300 .filter = h264_mp4toannexb_filter,
301 .flush = h264_mp4toannexb_flush,
302 .codec_ids = codec_ids,