[FFmpeg-user] Audio "bumps" in concatenated file

[Soeren Balko]

I just tested this scenario with the libfaac and mp3 encoders and basically
see the same result: there are "bumps" (brief drops in volume) at the glue
points of the transcoded segments.

I also tested the audio-only option (by mapping out the audio stream in the
first step) - but again, there are noticable bumps where the transcoded
segments are concatenated back together. Again, I tried both the mp3 and
the libfdk_aac codecs. Not sure what's going on here: it almost appears
like a bug to me...

Any thoughts?
Soeren


On Tue, Oct 22, 2013 at 7:39 PM, Soeren Balko <soeren at zfaas.com> wrote:

> I tested this for audio-only with the same result. Didn't check other
> audio codecs, though but will do and report on the outcome.
>
>
> On Tue, Oct 22, 2013 at 4:41 PM, Carl Eugen Hoyos <cehoyos at ag.or.at>wrote:
>
>> Soeren Balko <soeren <at> zfaas.com> writes:
>>
>> > ffmpeg -i segment00001.mov -bsf:v h264_mp4toannexb -f mpegts -acodec
>> > libfdk_aac -b:a 160k -ar 44100 -ac 2 -vcodec libx264 -profile:v baseline
>> > -x264-params level=4:ref=3 -g 90 -s hd1080 -r 29.97 -aspect 16/9 -b:v
>> 5400k
>> > segment00001.ts
>>
>> (If you are doing this only for performance reasons,
>> it is missing -threads 1, threads > 1 have an overhead.)
>>
>> Does it work for audio-only?
>> Did you test other audio encoders (mp2, ac3, native aac)?
>>
>> Carl Eugen
>>
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>
>