From e0cb89c354ea654bccc524a8a45321b93cb256d3 Mon Sep 17 00:00:00 2001 From: John Coiner Date: Sun, 12 Feb 2023 18:06:07 -0500 Subject: [PATCH] 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 --- libavformat/mpegtsenc.c | 48 +++++++++++++++++++++++++++++++++++------ 1 file changed, 41 insertions(+), 7 deletions(-) diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c index 00ad426086..ceed089587 100644 --- a/libavformat/mpegtsenc.c +++ b/libavformat/mpegtsenc.c @@ -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) {