[FFmpeg-devel] [PATCH 2/2] avformat/movenc: parse h264 packets to build Sync Sample and Recovery Point tables
James Almer
jamrial at gmail.com
Tue Jul 27 16:08:20 EEST 2021
Since we can't blindly trust the keyframe flag in packets and assume its
contents are a valid Sync Sample, do some basic bitstream parsing to build the
Sync Sample table in addition to a Random Access Recovery Point table.
Suggested-by: ffmpeg at fb.com
Signed-off-by: James Almer <jamrial at gmail.com>
---
libavformat/movenc.c | 125 +++++++++++++++++++++++++++++++++--
libavformat/movenc.h | 1 +
tests/ref/lavf-fate/h264.mp4 | 6 +-
3 files changed, 123 insertions(+), 9 deletions(-)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 57062f45c5..159e0261b7 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -34,13 +34,17 @@
#include "avc.h"
#include "libavcodec/ac3_parser_internal.h"
#include "libavcodec/dnxhddata.h"
+#include "libavcodec/h264.h"
+#include "libavcodec/h2645_parse.h"
#include "libavcodec/flac.h"
#include "libavcodec/get_bits.h"
+#include "libavcodec/golomb.h"
#include "libavcodec/internal.h"
#include "libavcodec/put_bits.h"
#include "libavcodec/vc1_common.h"
#include "libavcodec/raw.h"
+#include "libavcodec/sei.h"
#include "internal.h"
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
@@ -2537,7 +2541,9 @@ static int mov_preroll_write_stbl_atoms(AVIOContext *pb, MOVTrack *track)
if (!sgpd_entries)
return AVERROR(ENOMEM);
- av_assert0(track->par->codec_id == AV_CODEC_ID_OPUS || track->par->codec_id == AV_CODEC_ID_AAC);
+ av_assert0(track->par->codec_id == AV_CODEC_ID_OPUS ||
+ track->par->codec_id == AV_CODEC_ID_AAC ||
+ track->par->codec_id == AV_CODEC_ID_H264);
if (track->par->codec_id == AV_CODEC_ID_OPUS) {
for (i = 0; i < track->entry; i++) {
@@ -2545,7 +2551,7 @@ static int mov_preroll_write_stbl_atoms(AVIOContext *pb, MOVTrack *track)
int distance = 0;
for (j = i - 1; j >= 0; j--) {
roll_samples_remaining -= get_cluster_duration(track, j);
- distance++;
+ distance--;
if (roll_samples_remaining <= 0)
break;
}
@@ -2555,7 +2561,7 @@ static int mov_preroll_write_stbl_atoms(AVIOContext *pb, MOVTrack *track)
if (roll_samples_remaining > 0)
distance = 0;
/* Verify distance is a maximum of 32 (2.5ms) packets. */
- if (distance > 32)
+ if (distance < 32)
return AVERROR_INVALIDDATA;
if (i && distance == sgpd_entries[entries].roll_distance) {
sgpd_entries[entries].count++;
@@ -2566,10 +2572,22 @@ static int mov_preroll_write_stbl_atoms(AVIOContext *pb, MOVTrack *track)
sgpd_entries[entries].group_description_index = distance ? ++group : 0;
}
}
+ } else if (track->par->codec_id == AV_CODEC_ID_H264) {
+ for (i = 0; i < track->entry; i++) {
+ int distance = track->cluster[i].roll_distance;
+ if (i && distance == sgpd_entries[entries].roll_distance) {
+ sgpd_entries[entries].count++;
+ } else {
+ entries++;
+ sgpd_entries[entries].count = 1;
+ sgpd_entries[entries].roll_distance = distance;
+ sgpd_entries[entries].group_description_index = distance ? ++group : 0;
+ }
+ }
} else {
entries++;
sgpd_entries[entries].count = track->sample_count;
- sgpd_entries[entries].roll_distance = 1;
+ sgpd_entries[entries].roll_distance = -1;
sgpd_entries[entries].group_description_index = ++group;
}
entries++;
@@ -2588,7 +2606,7 @@ static int mov_preroll_write_stbl_atoms(AVIOContext *pb, MOVTrack *track)
avio_wb32(pb, group); /* entry_count */
for (i = 0; i < entries; i++) {
if (sgpd_entries[i].group_description_index) {
- avio_wb16(pb, -sgpd_entries[i].roll_distance); /* roll_distance */
+ avio_wb16(pb, sgpd_entries[i].roll_distance); /* roll_distance */
}
}
@@ -2639,7 +2657,9 @@ static int mov_write_stbl_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContext
if (track->cenc.aes_ctr) {
ff_mov_cenc_write_stbl_atoms(&track->cenc, pb);
}
- if (track->par->codec_id == AV_CODEC_ID_OPUS || track->par->codec_id == AV_CODEC_ID_AAC) {
+ if (track->par->codec_id == AV_CODEC_ID_OPUS ||
+ track->par->codec_id == AV_CODEC_ID_AAC ||
+ track->par->codec_id == AV_CODEC_ID_H264) {
mov_preroll_write_stbl_atoms(pb, track);
}
return update_size(pb, pos);
@@ -5150,6 +5170,96 @@ static int mov_parse_mpeg2_frame(AVPacket *pkt, uint32_t *flags)
return 0;
}
+static int mov_parse_h264_frame(AVPacket *pkt, MOVTrack *trk)
+{
+ GetBitContext gb;
+ const uint8_t *buf = pkt->data;
+ const uint8_t *buf_end = pkt->data + pkt->size;
+ uint32_t state = -1;
+ unsigned roll_distance = 0;
+ int nal_length_size = 0, nalsize;
+ int idr = 0;
+
+ if (!pkt->size)
+ return 0;
+ if (trk->vos_data && trk->vos_data[0] == 1) {
+ if (trk->vos_len < 5)
+ return 0;
+ nal_length_size = (trk->vos_data[4] & 0x03) + 1;
+ }
+
+ while (buf_end - buf >= 4) {
+ if (nal_length_size) {
+ int i = 0;
+ nalsize = get_nalsize(nal_length_size, buf, buf_end - buf, &i, NULL);
+ if (nalsize < 0)
+ break;
+ state = buf[nal_length_size];
+ buf += nal_length_size + 1;
+ } else {
+ buf = avpriv_find_start_code(buf, buf_end, &state);
+ if (buf >= buf_end)
+ break;
+ }
+
+ switch (state & 0x1f) {
+ case H264_NAL_IDR_SLICE:
+ idr = 1;
+ goto end;
+ case H264_NAL_SEI:
+ init_get_bits8(&gb, buf, buf_end - buf);
+ do {
+ GetBitContext gb_payload;
+ int ret, type = 0, size = 0;
+
+ do {
+ if (get_bits_left(&gb) < 8)
+ goto end;
+ type += show_bits(&gb, 8);
+ } while (get_bits(&gb, 8) == 255);
+ do {
+ if (get_bits_left(&gb) < 8)
+ goto end;
+ size += show_bits(&gb, 8);
+ } while (get_bits(&gb, 8) == 255);
+
+ if (size > get_bits_left(&gb) / 8)
+ goto end;
+
+ ret = init_get_bits8(&gb_payload, gb.buffer + get_bits_count(&gb) / 8, size);
+ if (ret < 0)
+ goto end;
+
+ switch (type) {
+ case SEI_TYPE_RECOVERY_POINT:
+ roll_distance = get_ue_golomb_long(&gb_payload);
+ break;
+ default:
+ break;
+ }
+ skip_bits_long(&gb, 8 * size);
+ } while (get_bits_left(&gb) > 0 && show_bits(&gb, 8) != 0x80);
+ break;
+ default:
+ break;
+ }
+ if (nal_length_size)
+ buf += nalsize - 1;
+ }
+
+end:
+ if (roll_distance != (int16_t)roll_distance)
+ roll_distance = 0;
+ trk->cluster[trk->entry].roll_distance = roll_distance;
+
+ if (idr) {
+ trk->cluster[trk->entry].flags |= MOV_SYNC_SAMPLE;
+ trk->has_keyframes++;
+ }
+
+ return 0;
+}
+
static void mov_parse_vc1_frame(AVPacket *pkt, MOVTrack *trk)
{
const uint8_t *start, *next, *end = pkt->data + pkt->size;
@@ -5740,6 +5850,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
trk->cluster[trk->entry].entries = samples_in_chunk;
trk->cluster[trk->entry].dts = pkt->dts;
trk->cluster[trk->entry].pts = pkt->pts;
+ trk->cluster[trk->entry].roll_distance = 0;
if (!trk->entry && trk->start_dts != AV_NOPTS_VALUE) {
if (!trk->frag_discont) {
/* First packet of a new fragment. We already wrote the duration
@@ -5821,6 +5932,8 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
if (par->codec_id == AV_CODEC_ID_VC1) {
mov_parse_vc1_frame(pkt, trk);
+ } else if (par->codec_id == AV_CODEC_ID_H264) {
+ mov_parse_h264_frame(pkt, trk);
} else if (par->codec_id == AV_CODEC_ID_TRUEHD) {
mov_parse_truehd_frame(pkt, trk);
} else if (pkt->flags & AV_PKT_FLAG_KEY) {
diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index af1ea0bce6..73bf73ce8f 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -56,6 +56,7 @@ typedef struct MOVIentry {
#define MOV_PARTIAL_SYNC_SAMPLE 0x0002
#define MOV_DISPOSABLE_SAMPLE 0x0004
uint32_t flags;
+ int16_t roll_distance;
AVProducerReferenceTime prft;
} MOVIentry;
diff --git a/tests/ref/lavf-fate/h264.mp4 b/tests/ref/lavf-fate/h264.mp4
index a9c3823c2c..c08ee4c7ae 100644
--- a/tests/ref/lavf-fate/h264.mp4
+++ b/tests/ref/lavf-fate/h264.mp4
@@ -1,3 +1,3 @@
-fe299ea5205b71a48281f917b1256a5d *tests/data/lavf-fate/lavf.h264.mp4
-547928 tests/data/lavf-fate/lavf.h264.mp4
-tests/data/lavf-fate/lavf.h264.mp4 CRC=0x9da2c999
+2812f617314d23474fcb23898b8a56ab *tests/data/lavf-fate/lavf.h264.mp4
+548084 tests/data/lavf-fate/lavf.h264.mp4
+tests/data/lavf-fate/lavf.h264.mp4 CRC=0x396f0829
--
2.32.0
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