[FFmpeg-user] White frames at the end

Mark Himsley mark.himsley at gmail.com
Wed May 30 09:50:01 CEST 2012


On May 25, 2012 3:20 PM, "Jaume Lopez" <glueball at gmail.com> wrote:
>
> Greetings,
>
> I've been trying to use ffmpeg to do a mov to mov conversion (with
> different size and bitrate in the output, otherwise it'd be useless of
> course).
>
> However, the output file has some white frames at the end. Running ffmpeg
> -i on both the original file and the resulting file, so I can see the
> details of the codification, reveals that the latter is 0.03 seconds
longer
> (pasting raw output below).
>

I've seen similar effects. For me it was caused by the audio codec adding a
small delay. If the delay is more than half a frame then QT adds the extra
white frame to the end.

As I understand it, from Googling and this mail list, some audio codecs
overlap audio frames, and add the audio from the overlapped parts together.
So, without adding a delay the first half of the first audio frame would be
at half level.

I haven't re-tested faac in a mov in the last year or so.

-- 
Mark


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