Opened 3 years ago

Closed 3 years ago

Last modified 18 months ago

#12893 closed Patch - Feature (Fixed)

Add decoding H.264 CC608/708 captions

Reported by: gregorio.gervasio@… Owned by: Peter Bennett
Priority: minor Milestone: 29.0
Component: MythTV - General Version: Master Head
Severity: medium Keywords:
Cc: Ticket locked: no

Description

The local cable company (Comcast) has converted more channels to H.264. These patches allow decoding of CC608/708 captions in these streams.

(NOTE: I'm not sure if the libav patch is right, but it looked like the A54 captions were only present whenever the field_poc check failed, so the code to save it wasn't getting executed. I moved that code to just before the check.)

Attachments (2)

0001-Changed-to-copy-A53-captions-before-field-check.patch (2.0 KB) - added by gregorio.gervasio@… 3 years ago.
libav patch for H.264 A53 captions
0002-Added-decoding-of-A53-captions.patch (2.7 KB) - added by gregorio.gervasio@… 3 years ago.
mythtv patch to add A53 caption decoding

Download all attachments as: .zip

Change History (14)

Changed 3 years ago by gregorio.gervasio@…

libav patch for H.264 A53 captions

Changed 3 years ago by gregorio.gervasio@…

mythtv patch to add A53 caption decoding

comment:1 Changed 3 years ago by jpoet

Thanks Gregorio.

It would be best if you could get the ffmpeg part committed to the upstream ffmpeg project. Or is it already? If it is, we need to sync to that version.

comment:2 Changed 3 years ago by gregorio.gervasio@…

From looking at FFmpeg git, it appears the same problem may exist in release 3.1. However, the affected code has been refactored in master and may not have the same problem.

comment:3 Changed 3 years ago by Peter Bennett

I tested this patch with MythTV master. With this patch, Comcast x264 subtitles work perfectly. I also verified that the Comcast mpeg-2 subtitles and subtitles on videos still work.

I tested VDPAU, VAAPI and Slim. All are OK.

Last edited 3 years ago by Peter Bennett (previous) (diff)

comment:4 Changed 3 years ago by Peter Bennett

Owner: set to Peter Bennett
Status: newassigned

comment:5 Changed 3 years ago by Stuart Auchterlonie

Milestone: unknown29.0
Version: UnspecifiedMaster Head

comment:6 Changed 3 years ago by Peter Bennett

I tested patch 0002 without the ffmpeg patch 0001. This works, I see the subtitles in h264 streams as well as in mpeg-2 streams. So it seems the ffmpeg patch may be unnecessary.

comment:7 Changed 3 years ago by gregorio.gervasio@…

The FFmpeg patch seems to be required for some of my recordings (eg. "Fear the Walking Dead" on AMC; strangely "The Walking Dead" on the same channel is fine without the patch).

Anyway, as I mentioned in comment2, this patch may not be relevant in more recent versions of FFmpeg.

comment:8 Changed 3 years ago by Peter Bennett

It seems that "Fear The Walking Dead" is not showing any more, only "The Walking Dead", so I cannot make a test recording. Can you give another example or else provide a sample of a file that does not work.

comment:9 Changed 3 years ago by Gregorio Gervasio <gregorio.gervasio@…>

In 59135e61f9c24ef2db30306afccc9cee1714d3d7/mythtv:

Add support for A53 captions.

Refs #12893

Signed-off-by: Peter Bennett <pbennett@…>

comment:10 Changed 3 years ago by Gregorio Gervasio <gregorio.gervasio@…>

In 49b6e2e1dc99eda391bae2b3119d92ed4e1cabe6/mythtv:

Add support for A53 captions.

Refs #12893

Signed-off-by: Peter Bennett <pbennett@…>
(cherry picked from commit 59135e61f9c24ef2db30306afccc9cee1714d3d7)

comment:11 Changed 3 years ago by Peter Bennett

Resolution: Fixed
Status: assignedclosed

Mark as fixed since the MythTV part is done. That fixes many cases. We will be moving to a new version of ffmpeg, which may address the remaining issue.

comment:12 Changed 18 months ago by Peter Bennett

Owner: changed from Peter Bennett to Peter Bennett
Note: See TracTickets for help on using tickets.