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[FFmpeg-devel,1/8] avformat/mpegts: add dvb ac3 descriptor metadata

Message ID 1595431659-664-1-git-send-email-lance.lmwang@gmail.com
State New
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Series [FFmpeg-devel,1/8] avformat/mpegts: add dvb ac3 descriptor metadata
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Commit Message

Limin Wang July 22, 2020, 3:27 p.m. UTC
From: Limin Wang <lance.lmwang@gmail.com>

Below is one metadata information for the ts with dvb ac3 descriptor audio:
 ./ffmpeg -i ac3_desc.ts
    ...
    Stream #0:1[0x294]: Audio: ac3 ([6][0][0][0] / 0x0006), 48000 Hz, 5.1(side), fltp, 448 kb/s
    Metadata:
      dvb.ac3_desc.component_type: 68
      dvb.ac3_desc.bsid: 6
      dvb.ac3_desc.mainid: 0

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
---
 libavformat/mpegts.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

Comments

Marton Balint July 22, 2020, 5:44 p.m. UTC | #1
On Wed, 22 Jul 2020, lance.lmwang@gmail.com wrote:

> From: Limin Wang <lance.lmwang@gmail.com>
>
> Below is one metadata information for the ts with dvb ac3 descriptor audio:
> ./ffmpeg -i ac3_desc.ts
>    ...
>    Stream #0:1[0x294]: Audio: ac3 ([6][0][0][0] / 0x0006), 48000 Hz, 5.1(side), fltp, 448 kb/s
>    Metadata:
>      dvb.ac3_desc.component_type: 68
>      dvb.ac3_desc.bsid: 6
>      dvb.ac3_desc.mainid: 0

I don't think it is a good idea to use metadata for this. See how dolby 
vision stores the descripor data, it is using side data and not metadata. 
Also it might make sense to create a generic mpegts descriptor side data 
type?

Regards.
Marton

>
> Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> ---
> libavformat/mpegts.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> index c6fd3e1..1ed7eaf 100644
> --- a/libavformat/mpegts.c
> +++ b/libavformat/mpegts.c
> @@ -2073,15 +2073,33 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
>         break;
>     case 0x6a: /* ac-3_descriptor */
>         {
> -            int component_type_flag = get8(pp, desc_end) & (1 << 7);
> +            uint8_t flags = get8(pp, desc_end);
> +            uint8_t component_type_flag = flags & (1 << 7);
> +            uint8_t bsid_flag           = flags & (1 << 6);
> +            uint8_t mainid_flag         = flags & (1 << 5);
> +            uint8_t asvc_flag           = flags & (1 << 4);
> +
>             if (component_type_flag) {
> -                int component_type = get8(pp, desc_end);
> +                uint8_t component_type = get8(pp, desc_end);
>                 int service_type_mask = 0x38;  // 0b00111000
>                 int service_type = ((component_type & service_type_mask) >> 3);
>                 if (service_type == 0x02 /* 0b010 */) {
>                     st->disposition |= AV_DISPOSITION_DESCRIPTIONS;
>                     av_log(ts ? ts->stream : fc, AV_LOG_DEBUG, "New track disposition for id %u: %u\n", st->id, st->disposition);
>                 }
> +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.component_type", component_type, 0);
> +            }
> +            if (bsid_flag) {
> +                uint8_t bsid = get8(pp, desc_end);
> +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.bsid", bsid, 0);
> +            }
> +            if (mainid_flag) {
> +                uint8_t mainid = get8(pp, desc_end);
> +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.mainid", mainid, 0);
> +            }
> +            if (asvc_flag) {
> +                uint8_t asvc = get8(pp, desc_end);
> +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.asvc", asvc, 0);
>             }
>         }
>         break;
> -- 
> 1.8.3.1
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Limin Wang July 22, 2020, 11:44 p.m. UTC | #2
On Wed, Jul 22, 2020 at 07:44:06PM +0200, Marton Balint wrote:
> 
> 
> On Wed, 22 Jul 2020, lance.lmwang@gmail.com wrote:
> 
> > From: Limin Wang <lance.lmwang@gmail.com>
> > 
> > Below is one metadata information for the ts with dvb ac3 descriptor audio:
> > ./ffmpeg -i ac3_desc.ts
> >    ...
> >    Stream #0:1[0x294]: Audio: ac3 ([6][0][0][0] / 0x0006), 48000 Hz, 5.1(side), fltp, 448 kb/s
> >    Metadata:
> >      dvb.ac3_desc.component_type: 68
> >      dvb.ac3_desc.bsid: 6
> >      dvb.ac3_desc.mainid: 0
> 
> I don't think it is a good idea to use metadata for this. See how dolby
> vision stores the descripor data, it is using side data and not metadata.
> Also it might make sense to create a generic mpegts descriptor side data
> type?

Thanks for the comments, I'll try to use side data for the descriptor instead. The descriptor is
codec related also, so I have no idea how to make it generic if need to export the field. EAC3
and AC3 may share same type, as it's use reserved bits to extend it. 

> 
> Regards.
> Marton
> 
> > 
> > Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> > ---
> > libavformat/mpegts.c | 22 ++++++++++++++++++++--
> > 1 file changed, 20 insertions(+), 2 deletions(-)
> > 
> > diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> > index c6fd3e1..1ed7eaf 100644
> > --- a/libavformat/mpegts.c
> > +++ b/libavformat/mpegts.c
> > @@ -2073,15 +2073,33 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
> >         break;
> >     case 0x6a: /* ac-3_descriptor */
> >         {
> > -            int component_type_flag = get8(pp, desc_end) & (1 << 7);
> > +            uint8_t flags = get8(pp, desc_end);
> > +            uint8_t component_type_flag = flags & (1 << 7);
> > +            uint8_t bsid_flag           = flags & (1 << 6);
> > +            uint8_t mainid_flag         = flags & (1 << 5);
> > +            uint8_t asvc_flag           = flags & (1 << 4);
> > +
> >             if (component_type_flag) {
> > -                int component_type = get8(pp, desc_end);
> > +                uint8_t component_type = get8(pp, desc_end);
> >                 int service_type_mask = 0x38;  // 0b00111000
> >                 int service_type = ((component_type & service_type_mask) >> 3);
> >                 if (service_type == 0x02 /* 0b010 */) {
> >                     st->disposition |= AV_DISPOSITION_DESCRIPTIONS;
> >                     av_log(ts ? ts->stream : fc, AV_LOG_DEBUG, "New track disposition for id %u: %u\n", st->id, st->disposition);
> >                 }
> > +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.component_type", component_type, 0);
> > +            }
> > +            if (bsid_flag) {
> > +                uint8_t bsid = get8(pp, desc_end);
> > +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.bsid", bsid, 0);
> > +            }
> > +            if (mainid_flag) {
> > +                uint8_t mainid = get8(pp, desc_end);
> > +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.mainid", mainid, 0);
> > +            }
> > +            if (asvc_flag) {
> > +                uint8_t asvc = get8(pp, desc_end);
> > +                av_dict_set_int(&st->metadata, "dvb.ac3_desc.asvc", asvc, 0);
> >             }
> >         }
> >         break;
> > -- 
> > 1.8.3.1
> > 
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel@ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > 
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
diff mbox series

Patch

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index c6fd3e1..1ed7eaf 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -2073,15 +2073,33 @@  int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
         break;
     case 0x6a: /* ac-3_descriptor */
         {
-            int component_type_flag = get8(pp, desc_end) & (1 << 7);
+            uint8_t flags = get8(pp, desc_end);
+            uint8_t component_type_flag = flags & (1 << 7);
+            uint8_t bsid_flag           = flags & (1 << 6);
+            uint8_t mainid_flag         = flags & (1 << 5);
+            uint8_t asvc_flag           = flags & (1 << 4);
+
             if (component_type_flag) {
-                int component_type = get8(pp, desc_end);
+                uint8_t component_type = get8(pp, desc_end);
                 int service_type_mask = 0x38;  // 0b00111000
                 int service_type = ((component_type & service_type_mask) >> 3);
                 if (service_type == 0x02 /* 0b010 */) {
                     st->disposition |= AV_DISPOSITION_DESCRIPTIONS;
                     av_log(ts ? ts->stream : fc, AV_LOG_DEBUG, "New track disposition for id %u: %u\n", st->id, st->disposition);
                 }
+                av_dict_set_int(&st->metadata, "dvb.ac3_desc.component_type", component_type, 0);
+            }
+            if (bsid_flag) {
+                uint8_t bsid = get8(pp, desc_end);
+                av_dict_set_int(&st->metadata, "dvb.ac3_desc.bsid", bsid, 0);
+            }
+            if (mainid_flag) {
+                uint8_t mainid = get8(pp, desc_end);
+                av_dict_set_int(&st->metadata, "dvb.ac3_desc.mainid", mainid, 0);
+            }
+            if (asvc_flag) {
+                uint8_t asvc = get8(pp, desc_end);
+                av_dict_set_int(&st->metadata, "dvb.ac3_desc.asvc", asvc, 0);
             }
         }
         break;