[Cin] Audio out of sync when rendering MP4s

[Andrew Randrianasulu]

чт, 1 февр. 2024 г., 01:00 Phyllis Smith via Cin <cin at lists.cinelerra-gg.org
>:

> Not sure if this will help or not, but the default Settings is "Align
> cursor to frames" as seen in the Settings pulldown.  But you might try to
> "Align cursor on frames when editing a video track and Align to samples
> when editing audio".  Check the box on for video and off for audio in the
> Settings pulldown.
>

well, I think when you have BOTH video and audio on timeline and you want
to move audio just a bit you must switch this mode  ... but I not tried
rendering yet, so I do not know if switching it back to default before
rendering will improve things or not ....


> On Wed, Jan 31, 2024 at 3:30 AM Matteo Bini via Cin <
> cin at lists.cinelerra-gg.org> wrote:
>
>> Hello Cinelerra GG developers,
>> I've found a strange behaviour in this great editing software.
>>
>> When I render my project, sometimes the audio is out of sync. Not all
>> the audio, but from a certain point, from half of the video the audio is
>> out of sync and it gets worst the more we get to the end of the video.
>> It's like latency piles up. I've only done MP4 renderings so far.
>>
>> My idea, but I don't know how to demonstrate it, is that ffmpeg doesn't
>> know how to render audio and video in sync, when there's some audio that
>> is not aligned on frames. Since I do a lot of precise audio editing in
>> my project, there are some audio cuts that are not aligned on frames.
>>
>> It's not a big problem, I just wanted to let you know. The solution is
>> very simple: render only the video track, then render the audio track in
>> WAV and then mux them together with ffmpeg, copying the video track and
>> encoding the audio one. This way the video is perfectly in sync with the
>> audio.
>>
>> The strange thing is that, when I watch my project from the compositor
>> window, audio and video are in sync.
>>
>> Thank you for making Cinelerra GG a really great free software.
>>
>> --
>> Matteo Bini
>> --
>> Cin mailing list
>> Cin at lists.cinelerra-gg.org
>> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>>
> --
> Cin mailing list
> Cin at lists.cinelerra-gg.org
> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>
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