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

[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.


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