[MPlayer-users] encoding at faster speed

[Art]

On Mon, Jun 2, 2008 at 12:10 AM, Nico Sabbi <Nicola.Sabbi at poste.it> wrote:
> Il Monday 02 June 2008 08:48:57 Art ha scritto:
>> I would like to encode a video lecture downloaded from the web to play
>> at about 1.5 times the speed. The device I playback on has no way to
>> change the speed of playback, as with mplayer -speed, which works
>> perfectly for fast playback on my work desktop. Is there a way to do
>> this with mencoder? Or other software? These lectures are painful to
>> watch at regular speed.
>
> mencoder -ofps N -af lavcresample=M ...
> when N = fps*speed and M=original samplerate * speed
> but be aware that basically very few  audio codecs accept
> arbitrary sample rates (pcm being the only one I can think of)
>

I couldn't get this to work. I think it is the problem you described
about arbitrary sample rates (like lame doesnt work with 76800). Also,
this is over my head so if I get a better understanding, I may do
better.

Is there a way to do this in two steps? There is blog post:

http://mark.santaniello.com/archives/260

for pitch corrected playback (I actually haven't gotten the pitch part
working). Could I use mplayer and output the fast audio to a separate
file and use this file as an input to mencoder along with fast video
with  -ofps x1.6?

>>
>> Can someone also tell me how to increase the coding volume? I am new
>> to this. The below is the encoding command I use:
>>
>> mencoder -quiet -vf scale=320:240 $1 -o $2 -of avi -ofps 15 -ovc lavc
>> -oac mp3lame -lavcopts
>> vcodec=mpeg4:vbitrate=230:acodec=mp3:abitrate=64
>>
>> Thanks,
>> Art.
>
> test -af volume=

Thanks that was helpful.

Art.