avformat/mpegtsenc: re-emit extradata ahead of IDR pictures even if AUD is already present

Current mpegtsenc code only inserts SPS/PPS from extradata before IDR frames if
AUD is also inserted.

Unfortunately some encoders may preface a key frame with an AUD, but no
SPS/PPS. In that case current code does not repeat the "extradata" and the
resulting HLS stream may become noncompliant and unjoinable.

Fix this by always inserting SPS/PPS and moving AUD to the beginning of the
packet if it is already present.

Fixes ticket #10148.

Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
John Coiner 2023-02-12 18:06:07 -05:00 committed by Marton Balint
parent 3807fbd90a
commit e0cb89c354

View File

@ -29,6 +29,8 @@
#include "libavcodec/ac3_parser_internal.h"
#include "libavcodec/avcodec.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/h264.h"
#include "libavcodec/startcode.h"
#include "avformat.h"
@ -1877,6 +1879,7 @@ static int mpegts_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
if (st->codecpar->codec_id == AV_CODEC_ID_H264) {
const uint8_t *p = buf, *buf_end = p + size;
const uint8_t *found_aud = NULL, *found_aud_end = NULL;
uint32_t state = -1;
int extradd = (pkt->flags & AV_PKT_FLAG_KEY) ? st->codecpar->extradata_size : 0;
int ret = ff_check_h264_startcode(s, st, pkt);
@ -1886,27 +1889,58 @@ static int mpegts_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
if (extradd && AV_RB24(st->codecpar->extradata) > 1)
extradd = 0;
/* Ensure that all pictures are prefixed with an AUD, and that
* IDR pictures are also prefixed with SPS and PPS. SPS and PPS
* are assumed to be available in 'extradata' if not found in-band. */
do {
p = avpriv_find_start_code(p, buf_end, &state);
av_log(s, AV_LOG_TRACE, "nal %"PRId32"\n", state & 0x1f);
if ((state & 0x1f) == 7)
if ((state & 0x1f) == H264_NAL_SPS)
extradd = 0;
} while (p < buf_end && (state & 0x1f) != 9 &&
(state & 0x1f) != 5 && (state & 0x1f) != 1);
if ((state & 0x1f) != 5)
if ((state & 0x1f) == H264_NAL_AUD) {
found_aud = p - 4; // start of the 0x000001 start code.
found_aud_end = p + 1; // first byte past the AUD.
if (found_aud < buf)
found_aud = buf;
if (buf_end < found_aud_end)
found_aud_end = buf_end;
}
} while (p < buf_end
&& (state & 0x1f) != H264_NAL_IDR_SLICE
&& (state & 0x1f) != H264_NAL_SLICE
&& (extradd > 0 || !found_aud));
if ((state & 0x1f) != H264_NAL_IDR_SLICE)
extradd = 0;
if ((state & 0x1f) != 9) { // AUD NAL
if (!found_aud) {
/* Prefix 'buf' with the missing AUD, and extradata if needed. */
data = av_malloc(pkt->size + 6 + extradd);
if (!data)
return AVERROR(ENOMEM);
memcpy(data + 6, st->codecpar->extradata, extradd);
memcpy(data + 6 + extradd, pkt->data, pkt->size);
AV_WB32(data, 0x00000001);
data[4] = 0x09;
data[4] = H264_NAL_AUD;
data[5] = 0xf0; // any slice type (0xe) + rbsp stop one bit
buf = data;
size = pkt->size + 6 + extradd;
} else if (extradd != 0) {
/* Move the AUD up to the beginning of the frame, where the H.264
* spec requires it to appear. Emit the extradata after it. */
PutByteContext pb;
const int new_pkt_size = pkt->size + 1 + extradd;
data = av_malloc(new_pkt_size);
if (!data)
return AVERROR(ENOMEM);
bytestream2_init_writer(&pb, data, new_pkt_size);
bytestream2_put_byte(&pb, 0x00);
bytestream2_put_buffer(&pb, found_aud, found_aud_end - found_aud);
bytestream2_put_buffer(&pb, st->codecpar->extradata, extradd);
bytestream2_put_buffer(&pb, pkt->data, found_aud - pkt->data);
bytestream2_put_buffer(&pb, found_aud_end, buf_end - found_aud_end);
av_assert0(new_pkt_size == bytestream2_tell_p(&pb));
buf = data;
size = new_pkt_size;
}
} else if (st->codecpar->codec_id == AV_CODEC_ID_AAC) {
if (pkt->size < 2) {