[vlc-devel] FIXED!!! Re: mp3 transcoding creates slow audio (was Re: Slow audio when streaming flv

[Dave Still]

On Jul 8, 2008, at 5:38 AM, Rov Juvano wrote:

> On Mon, Jul 07, 2008 at 05:05:43PM -0700, Dave Still wrote:
>> I did some more testing, and it appears that the slow audio is
>> happening for any a/v file where audio is transcoded is transcoded to
>> mp3.  For example, the following command-line:
>>
>> ./VLC.app/Contents/MacOS/VLC -vvv -I dummy ~/Movies/makeup.wmv --sout
>> "#transcode
>> {vcodec
>> =
>> mp4v
>> ,acodec
>> =
>> mp3
>> ,samplerate
>> =
>> 22050
>> ,ab
>> =
>> 128
>> ,vb
>> =
>> 512,width=320,height=240,channels=2}:std{access=file,dst=stream.mov}"
>> --audio-filter scaletempo vlc://quit
>>
>> The resulting stream.mov plays back in QuickTime, but the audio is
>> hella-slow.  Result is the same with or without the scaletempo audio
>> filter.
>>
>> - Dave
>
> I narrowed this down to:
> commit 79bd720139a011cd603efed8b6f7be297e6d55ce
> Date:   Tue Apr 8 16:00:22 2008 +0200
>
>    When specifying --sout-transcode-samplerate and --sout-transcode- 
> channel, set the OUTPUT format instead of the INPUT
>
>    Fix resampling when using mp4a (faac is the only option atm)
>
>
> With the following patch, transcode keeps the pitch when
> resampling to an mp3.  I had to specify acodec=mpga to find
> an encoder.
>
This fixed it!  Thank you!  I had to modify your patch slightly to  
include mp3, but now mp3 transcoding pitch is working!  For some  
reason I couldn't get this to work back in April when funman suggested  
the same fix, so thank you!  I've attached the updated patch that  
works with acodec=mp3.

Many thanks!
- Dave

> --
> rovjuvano
> <transcode-mp3.patch>

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