[FFmpeg-devel] [PATCH] avformat/mpegtsenc: Fix mpegts_write_pes() for private_stream_2 and other types

Marton Balint cus at passwd.hu
Tue Apr 20 00:01:45 EEST 2021



On Tue, 20 Apr 2021, zheng qian wrote:

> According to the PES packet definition defined in Table 2-17
> of ISO_IEC_13818-1 specification, some fields like PTS/DTS or
> pes_extension could only appears if the stream_id meets the
> condition:
>
> if (stream_id != 0xBC &&  // program_stream_map
> stream_id != 0xBE &&  // padding_stream
> stream_id != 0xBF &&  // private_stream_2
> stream_id != 0xF0 &&  // ECM
> stream_id != 0xF1 &&  // EMM
> stream_id != 0xFF &&  // program_stream_directory
> stream_id != 0xF2 &&  // DSMCC_stream
> stream_id != 0xF8)     // ITU-T Rec. H.222.1 type E stream
>
> And the following stream_id types don't have fields like PTS/DTS:
>
> else if ( stream_id == program_stream_map
> || stream_id == private_stream_2
> || stream_id == ECM
> || stream_id == EMM
> || stream_id == program_stream_directory
> || stream_id == DSMCC_stream
> || stream_id == ITU-T Rec. H.222.1 type E stream ) {
>    for (i = 0; i < PES_packet_length; i++) {
>        PES_packet_data_byte
>    }
> }
>
> Current implementation skipped the judgement of stream_id
> causing some kind of stream like private_stream_2 to be
> incorrectly written with PTS/DTS field. For example,
> Japan DTV transmits news and alerts through ARIB superimpose
> that utilizes private_stream_2 still could not be remuxed
> correctly for now.
>
> This patch fixes the remuxing of private_stream_2 and other
> stream_id types.
>
> Signed-off-by: zheng qian <xqq at xqq.im>
> ---
> libavformat/mpegtsenc.c | 108 ++++++++++++++++++++++------------------
> 1 file changed, 60 insertions(+), 48 deletions(-)
>
> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> index f302af84ff..da8fb381e5 100644
> --- a/libavformat/mpegtsenc.c
> +++ b/libavformat/mpegtsenc.c
> @@ -1445,28 +1445,28 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream *st,
>             is_dvb_teletext = 0;
>             if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
>                 if (st->codecpar->codec_id == AV_CODEC_ID_DIRAC)
> -                    *q++ = STREAM_ID_EXTENDED_STREAM_ID;
> +                    stream_id = STREAM_ID_EXTENDED_STREAM_ID;
>                 else
> -                    *q++ = STREAM_ID_VIDEO_STREAM_0;
> +                    stream_id = STREAM_ID_VIDEO_STREAM_0;
>             } else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
>                        (st->codecpar->codec_id == AV_CODEC_ID_MP2 ||
>                         st->codecpar->codec_id == AV_CODEC_ID_MP3 ||
>                         st->codecpar->codec_id == AV_CODEC_ID_AAC)) {
> -                *q++ = STREAM_ID_AUDIO_STREAM_0;
> +                stream_id = STREAM_ID_AUDIO_STREAM_0;
>             } else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
>                         st->codecpar->codec_id == AV_CODEC_ID_AC3 &&
>                         ts->m2ts_mode) {
> -                *q++ = STREAM_ID_EXTENDED_STREAM_ID;
> +                stream_id = STREAM_ID_EXTENDED_STREAM_ID;
>             } else if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA &&
>                        st->codecpar->codec_id == AV_CODEC_ID_TIMED_ID3) {
> -                *q++ = STREAM_ID_PRIVATE_STREAM_1;
> +                stream_id = STREAM_ID_PRIVATE_STREAM_1;
>             } else if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA) {
> -                *q++ = stream_id != -1 ? stream_id : STREAM_ID_METADATA_STREAM;
> +                stream_id = stream_id != -1 ? stream_id : STREAM_ID_METADATA_STREAM;
>
>                 if (stream_id == STREAM_ID_PRIVATE_STREAM_1) /* asynchronous KLV */
>                     pts = dts = AV_NOPTS_VALUE;
>             } else {
> -                *q++ = STREAM_ID_PRIVATE_STREAM_1;
> +                stream_id = STREAM_ID_PRIVATE_STREAM_1;
>                 if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
>                     if (st->codecpar->codec_id == AV_CODEC_ID_DVB_SUBTITLE) {
>                         is_dvb_subtitle = 1;
> @@ -1475,6 +1475,7 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream *st,
>                     }
>                 }
>             }
> +            *q++ = stream_id;

This is a purley cosmetic change so far, so it should be a separate patch 
from the functional change.

>             header_len = 0;
>             flags      = 0;
>             if (pts != AV_NOPTS_VALUE) {
> @@ -1524,50 +1525,61 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream *st,
>             }
>             *q++ = len >> 8;
>             *q++ = len;
> -            val  = 0x80;
> -            /* data alignment indicator is required for subtitle and data streams */
> -            if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE || st->codecpar->codec_type == AVMEDIA_TYPE_DATA)
> -                val |= 0x04;
> -            *q++ = val;
> -            *q++ = flags;
> -            *q++ = header_len;
> -            if (pts != AV_NOPTS_VALUE) {
> -                write_pts(q, flags >> 6, pts);
> -                q += 5;
> -            }
> -            if (dts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE && dts != pts) {
> -                write_pts(q, 1, dts);
> -                q += 5;
> -            }
> -            if (pes_extension && st->codecpar->codec_id == AV_CODEC_ID_DIRAC) {
> -                flags = 0x01;  /* set PES_extension_flag_2 */
> -                *q++  = flags;
> -                *q++  = 0x80 | 0x01; /* marker bit + extension length */
> -                /* Set the stream ID extension flag bit to 0 and
> -                 * write the extended stream ID. */
> -                *q++ = 0x00 | 0x60;
> -            }
> -            /* For Blu-ray AC3 Audio Setting extended flags */
> -            if (ts->m2ts_mode &&
> -                pes_extension &&
> -                st->codecpar->codec_id == AV_CODEC_ID_AC3) {
> -                flags = 0x01; /* set PES_extension_flag_2 */
> +
> +            if (stream_id != 0xBC &&  // program_stream_map
> +                stream_id != 0xBE &&  // padding_stream
> +                stream_id != 0xBF &&  // private_stream_2
> +                stream_id != 0xF0 &&  // ECM
> +                stream_id != 0xF1 &&  // EMM
> +                stream_id != 0xFF &&  // program_stream_directory
> +                stream_id != 0xF2 &&  // DSMCC_stream
> +                stream_id != 0xF8) {  // ITU-T Rec. H.222.1 type E stream
> +
> +                val  = 0x80;
> +                /* data alignment indicator is required for subtitle and data streams */
> +                if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE || st->codecpar->codec_type == AVMEDIA_TYPE_DATA)
> +                    val |= 0x04;
> +                *q++ = val;
>                 *q++ = flags;
> -                *q++ = 0x80 | 0x01; /* marker bit + extension length */
> -                *q++ = 0x00 | 0x71; /* for AC3 Audio (specifically on blue-rays) */
> -            }
> +                *q++ = header_len;
> +                if (pts != AV_NOPTS_VALUE) {
> +                    write_pts(q, flags >> 6, pts);
> +                    q += 5;
> +                }
> +                if (dts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE && dts != pts) {
> +                    write_pts(q, 1, dts);
> +                    q += 5;
> +                }
> +                if (pes_extension && st->codecpar->codec_id == AV_CODEC_ID_DIRAC) {
> +                    flags = 0x01;  /* set PES_extension_flag_2 */
> +                    *q++  = flags;
> +                    *q++  = 0x80 | 0x01; /* marker bit + extension length */
> +                    /* Set the stream ID extension flag bit to 0 and
> +                    * write the extended stream ID. */
> +                    *q++ = 0x00 | 0x60;
> +                }
> +                /* For Blu-ray AC3 Audio Setting extended flags */
> +                if (ts->m2ts_mode &&
> +                    pes_extension &&
> +                    st->codecpar->codec_id == AV_CODEC_ID_AC3) {
> +                    flags = 0x01; /* set PES_extension_flag_2 */
> +                    *q++ = flags;
> +                    *q++ = 0x80 | 0x01; /* marker bit + extension length */
> +                    *q++ = 0x00 | 0x71; /* for AC3 Audio (specifically on blue-rays) */
> +                }
>
>
> -            if (is_dvb_subtitle) {
> -                /* First two fields of DVB subtitles PES data:
> -                 * data_identifier: for DVB subtitle streams shall be coded with the value 0x20
> -                 * subtitle_stream_id: for DVB subtitle stream shall be identified by the value 0x00 */
> -                *q++ = 0x20;
> -                *q++ = 0x00;
> -            }
> -            if (is_dvb_teletext) {
> -                memset(q, 0xff, pes_header_stuffing_bytes);
> -                q += pes_header_stuffing_bytes;
> +                if (is_dvb_subtitle) {
> +                    /* First two fields of DVB subtitles PES data:
> +                    * data_identifier: for DVB subtitle streams shall be coded with the value 0x20
> +                    * subtitle_stream_id: for DVB subtitle stream shall be identified by the value 0x00 */
> +                    *q++ = 0x20;
> +                    *q++ = 0x00;
> +                }
> +                if (is_dvb_teletext) {
> +                    memset(q, 0xff, pes_header_stuffing_bytes);
> +                    q += pes_header_stuffing_bytes;
> +                }
>             }

Aviod the reindentation to make the patch easier to read. Do reindentation 
in a subsequent cosmetic only patch.

Thanks,
Marton


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