[FFmpeg-devel] [PATCH v2] avformat/mpegtsenc: support DVB 6A descriptor for AC-3
Guangxin Xu
oddstone at gmail.com
Sat Aug 15 18:38:29 EEST 2020
On Sat, Aug 15, 2020 at 10:28 PM <lance.lmwang at gmail.com> wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
>
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
> configure | 2 +-
> libavformat/mpegts.h | 16 ++++++++++
> libavformat/mpegtsenc.c | 84
> +++++++++++++++++++++++++++++++++++++++++++++++--
> 3 files changed, 99 insertions(+), 3 deletions(-)
>
> diff --git a/configure b/configure
> index d4a1fea..a9d87b2 100755
> --- a/configure
> +++ b/configure
> @@ -3324,7 +3324,7 @@ mp3_demuxer_select="mpegaudio_parser"
> mp3_muxer_select="mpegaudioheader"
> mp4_muxer_select="mov_muxer"
> mpegts_demuxer_select="iso_media"
> -mpegts_muxer_select="adts_muxer latm_muxer h264_mp4toannexb_bsf
> hevc_mp4toannexb_bsf"
> +mpegts_muxer_select="ac3_parser adts_muxer latm_muxer
> h264_mp4toannexb_bsf hevc_mp4toannexb_bsf"
> mpegtsraw_demuxer_select="mpegts_demuxer"
> mxf_muxer_select="golomb pcm_rechunk_bsf"
> mxf_d10_muxer_select="mxf_muxer"
> diff --git a/libavformat/mpegts.h b/libavformat/mpegts.h
> index fe10b38..d70b25d 100644
> --- a/libavformat/mpegts.h
> +++ b/libavformat/mpegts.h
> @@ -175,6 +175,22 @@ typedef struct Mp4Descr {
> SLConfigDescr sl;
> } Mp4Descr;
>
> +/*
> + * ETSI 300 468 descriptor 0x6A(AC-3)
> + * Refer to: ETSI EN 300 468 V1.11.1 (2010-04) (SI in DVB systems)
> + */
> +typedef struct DVBAC3Descriptor {
> + uint8_t component_type_flag;
> + uint8_t bsid_flag;
> + uint8_t mainid_flag;
> + uint8_t asvc_flag;
> + uint8_t reserved_flags;
> + uint8_t component_type;
> + uint8_t bsid;
> + uint8_t mainid;
> + uint8_t asvc;
> +} DVBAC3Descriptor;
> +
> /**
> * Parse an MPEG-2 descriptor
> * @param[in] fc Format context (used for logging only)
> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> index 718ddab..876ba99 100644
> --- a/libavformat/mpegtsenc.c
> +++ b/libavformat/mpegtsenc.c
> @@ -27,6 +27,7 @@
> #include "libavutil/mathematics.h"
> #include "libavutil/opt.h"
>
> +#include "libavcodec/ac3_parser_internal.h"
> #include "libavcodec/internal.h"
>
> #include "avformat.h"
> @@ -244,6 +245,8 @@ typedef struct MpegTSWriteStream {
> /* For Opus */
> int opus_queued_samples;
> int opus_pending_trim_start;
> +
> + DVBAC3Descriptor *dvb_ac3_desc;
> } MpegTSWriteStream;
>
> static void mpegts_write_pat(AVFormatContext *s)
> @@ -486,9 +489,28 @@ static int mpegts_write_pmt(AVFormatContext *s,
> MpegTSService *service)
> case AVMEDIA_TYPE_AUDIO:
> if (ts->flags & MPEGTS_FLAG_SYSTEM_B) {
> if (codec_id == AV_CODEC_ID_AC3) {
> + DVBAC3Descriptor *dvb_ac3_desc = ts_st->dvb_ac3_desc;
>
need check ts_st->dvb_ac3_desc?
+
> *q++=0x6a; // AC3 descriptor see A038 DVB SI
> - *q++=1; // 1 byte, all flags sets to 0
> - *q++=0; // omit all fields...
> + if (dvb_ac3_desc) {
> + int len = 1 +
> + !!(dvb_ac3_desc->component_type_flag) +
> + !!(dvb_ac3_desc->bsid_flag) +
> + !!(dvb_ac3_desc->mainid_flag) +
> + !!(dvb_ac3_desc->asvc_flag);
> +
> + *q++ = len;
> + *q++ = dvb_ac3_desc->component_type_flag << 7 |
> dvb_ac3_desc->bsid_flag << 6 |
> + dvb_ac3_desc->mainid_flag << 5 |
> dvb_ac3_desc->asvc_flag << 4;
> +
> + if (dvb_ac3_desc->component_type_flag) *q++ =
> dvb_ac3_desc->component_type;
> + if (dvb_ac3_desc->bsid_flag) *q++ =
> dvb_ac3_desc->bsid;
> + if (dvb_ac3_desc->mainid_flag) *q++ =
> dvb_ac3_desc->mainid;
> + if (dvb_ac3_desc->asvc_flag) *q++ =
> dvb_ac3_desc->asvc;
> + } else {
> + *q++=1; // 1 byte, all flags sets to 0
> + *q++=0; // omit all fields...
> + }
> } else if (codec_id == AV_CODEC_ID_EAC3) {
> *q++=0x7a; // EAC3 descriptor see A038 DVB SI
> *q++=1; // 1 byte, all flags sets to 0
> @@ -1843,6 +1865,63 @@ static int
> mpegts_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
> * need to count the samples of that too! */
> av_log(s, AV_LOG_WARNING, "Got MPEG-TS formatted Opus data,
> unhandled");
> }
> + } else if (st->codecpar->codec_id == AV_CODEC_ID_AC3 &&
> !ts_st->dvb_ac3_desc) {
> + AC3HeaderInfo *hdr = NULL;
> +
> + if (avpriv_ac3_parse_header(&hdr, pkt->data, pkt->size) >= 0) {
> + uint8_t number_of_channels_flag;
> + uint8_t service_type_flag;
> + uint8_t full_service_flag = 1;
> + DVBAC3Descriptor *dvb_ac3_desc;
> +
> + dvb_ac3_desc = av_mallocz(sizeof(*dvb_ac3_desc));
> + if (!dvb_ac3_desc) {
> + av_free(hdr);
> + return AVERROR(ENOMEM);
> + }
> +
> + service_type_flag = hdr->bitstream_mode;
> + switch (hdr->channel_mode) {
> + case AC3_CHMODE_DUALMONO:
> + number_of_channels_flag = 1;
> + break;
> + case AC3_CHMODE_MONO:
> + number_of_channels_flag = 0;
> + break;
> + case AC3_CHMODE_STEREO:
> + if (hdr->dolby_surround_mode == AC3_DSURMOD_ON)
> + number_of_channels_flag = 3;
> + else
> + number_of_channels_flag = 2;
> + break;
> + case AC3_CHMODE_3F:
> + case AC3_CHMODE_2F1R:
> + case AC3_CHMODE_3F1R:
> + case AC3_CHMODE_2F2R:
> + case AC3_CHMODE_3F2R:
> + number_of_channels_flag = 4;
> + break;
> + default: /* reserved */
> + number_of_channels_flag = 7;
> + break;
> + }
> +
> + if (service_type_flag == 1 || service_type_flag == 4 ||
> + (service_type_flag == 7 && !number_of_channels_flag))
> + full_service_flag = 0;
> +
> + dvb_ac3_desc->component_type_flag = 1;
> + dvb_ac3_desc->component_type = (full_service_flag << 6)
> |
> + ((service_type_flag & 0x7) <<
> 3) |
> + (number_of_channels_flag & 0x7);
> + dvb_ac3_desc->bsid_flag = 1;
> + dvb_ac3_desc->bsid = hdr->bitstream_id;
> + dvb_ac3_desc->mainid_flag = 0;
> + dvb_ac3_desc->asvc_flag = 0;
> +
> + ts_st->dvb_ac3_desc = dvb_ac3_desc;
> + }
> + av_free(hdr);
> }
>
> if (ts_st->payload_size && (ts_st->payload_size + size >
> ts->pes_payload_size ||
> @@ -1934,6 +2013,7 @@ static void mpegts_deinit(AVFormatContext *s)
> AVStream *st = s->streams[i];
> MpegTSWriteStream *ts_st = st->priv_data;
> if (ts_st) {
> + av_freep(&ts_st->dvb_ac3_desc);
> av_freep(&ts_st->payload);
> if (ts_st->amux) {
> avformat_free_context(ts_st->amux);
> --
> 1.8.3.1
>
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