[FFmpeg-devel] [PATCH] avformat/movenc: Remove experimental status of TrueHD-in-MP4 muxing (mlpa)

[Nomis101]

Am 11.11.22 um 14:48 schrieb Nomis101:
> Am 11.11.22 um 14:05 schrieb Jan Ekström:
>> On Wed, Nov 9, 2022 at 9:15 PM Nomis101 <Nomis101 at web.de> wrote:
>>>
>>> Am 06.11.22 um 21:57 schrieb Carl Eugen Hoyos:
>>>> Am Sa., 5. Nov. 2022 um 22:31 Uhr schrieb Nomis101 <Nomis101 at web.de>:
>>>>>
>>>>> Support for mlpa muxing was added back in 2019:
>>>>> http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=808a6717e0c584738c60a109afd6d47f4973d619
>>>>> But it was hidden back then behind FF_COMPLIANCE_EXPERIMENTAL, because it was new and there was no
>>>>> support from other applications.
>>>>>
>>>>> In the meantime there is support in MediaInfo: MediaArea/MediaInfoLib#1258
>>>>> For VLC: videolan/vlc at 9c49f40
>>>>> Since version 7.3.4 for Infuse: 
>>>>> https://community.firecore.com/t/dolby-mlp-mlpa-codec-support/26100/31
>>>>> And mpv does support this as well.
>>>>
>>>> If there was ever a good reason to make this feature experimental,
>>>> I don't think these applications change the situation.
>>>
>>>
>>> The reason to make this experimental was, because there was no implementation from others at this 
>>> time.
>>> http://ffmpeg.org/pipermail/ffmpeg-devel/2019-August/248435.html
>>> Now, there is implementation from others. How many implementation from others will be needed to
>>> change the situation?
>>>
>>
>> I think the main thing was to have the feature verified by non-FFmpeg
>> things. Basically, if you wrote out a TrueHD file and actual 3rd party
>> implementations that didn't just utilize FFmpeg for reading would
>> happily read it, then the flag should be removed.
>>
>> If the VLC commit did not specifically say "we did it like this to
>> enable support for files that FFmpeg generated" but rather that they
>> followed the spec, then that's one alternative implementation indeed.
>> And if MediaInfo or that Infuse thing also added support for the exact
>> same mapping and that neither specifically utilized FFmpeg internally,
>> then those also apply.
>>
>> Finally, I think the D company has a git repo for "dlb_mp4base", you
>> could check if that supports this mapping.
>>
>> Best regards,
>> Jan
> 
> OK, thanks Jan for the detailed explanation. I will check D company. Infuse has implemented it 
> independently of FFmpeg.  VLC and Mediainfo I do not know. The specs were mentioned in the bug, but 
> also FFmpeg. But both would not implement anything if there was no specification for it.


There is also support in "dlb_mp4base":
https://github.com/DolbyLaboratories/dlb_mp4base/blob/8da6d4a8fc095a88349fbdac33e7e68fb3b93649/src/mp4_muxer.c#L149


> 
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