[mythtv] Call for testing branch devel/ffmpeg-resync (mpegts-harmonize)

Scott Theisen scott.the.elm at gmail.com
Tue Aug 2 18:44:55 UTC 2022

On 8/1/22 10:47, John Pilkington wrote:
> On 29/07/2022 18:17, Scott Theisen wrote:
>> On 7/29/22 09:35, Klaas de Waal wrote:
>>> This is the commit that causes a failure on BBC streams with 
>>> the devel/ffmpeg-resync branch:
>>> 1bba2b59941d575ade7206d0ba52a556f5d3e672 is the first bad commit
>>> commit 1bba2b59941d575ade7206d0ba52a556f5d3e672
>>> Author: Scott Theisen <scott.the.elm at gmail.com>
>>> Date:   Fri Mar 18 00:34:50 2022 -0400
>>> The problem is not in the MHEG processing but in the presence of the 
>>> streams that contain the additional MHEG information.
>>> With MHEG processing disabled it crashes in the same way.
>>> Details:
>>> - BBC streams received from Astra-2 satellite (a.k.a. Freesat).
>>> - When playing a recording, the failure is on stopping playback.
>>> - When using Live TV the failure is immediate, probably because Live 
>>> TV does a start / stop / start sequence when starting playback.
>>> Could just be that your new reference counting code is not very good 
>>> at counting....
>> I think that is the problem John was having. add_section_stream() 
>> reuses the SectionContext if it already exists, but this causes the 
>> same pointer to be added to multiple streams' `priv_data`, causing 
>> crashes when it is then double freed.  My patch prevented this double 
>> freeing, but the DSMCC_B code is never executed, so it doesn't work.
>> However, with my new MHEG sample from John, I can't bring up the menu 
>> for the interactive TV after only 6 commits, so I am working through 
>> that commit splitting it into smaller pieces to find what broke MHEG.
>> Regards,
>> Scott
> Largely as an excercise-for-the-student, I now have a build from 
> Scott's pull request, labelled 32Pre4276, git f27fd9c, installed and 
> running. The MHEG menu works on the recent clip, and also on an HD 
> clip from last year where the cutting had retained the full set of 
> streams.

Good to hear that my new version works correctly.

> Both show today's date...

This is probably intentional since it is intended to be used with live 
TV.  What I think is happening is the MHEG program is calling 
GetCurrentDate() and then FormatDate() instead of hard coding into the 
stream what date (and time) it wants formatted.



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