How do you batch reencode audio in mp4s? - now starting project over

[yoda313]

Ok here it goes. I had downloaded a series of flv videos off the internet. I wanted to watch them on my psp (1000 fat version). I used format factory to do this to mp4 avc. On one test I used the psp 480x272 widescreen profile and it worked just fine. I did it on the rest of the files I had but upon copying them the psp does not see them (the second time the only profile I had access to was the mp4 - mobile generic setting for 480x272 avc).

The only difference I can tell from the two files that will and won't play is the audio. One is at 24000 hz 68kpbs stereo (the psp profile on the format factory option setting and the other (the generic mobile format mp4 option) - is 44100 hz 126kps stereo.

Please let me know the best (ie easiest) batch option available to remix the audio to 24000 hz 68kpbs so the psp will play the videos.

There are 25 files in total that have been converted to mp4 from flv. I'm hoping that it will be quicker to reencode the audio on each rather than starting from scratch and reverting to the flvs (which thankfully I still have). It took about 2+ hours to encode the original batch of 25. In the end if it is more hassle than it is worth to reencode the audio I will in the end start over.

FYI these videos are in a foreign language other than english so sync isn't 100% critical though things like sound effects would get annoying if the synch drifts too much upon reencoding.

Thanks for suggestions.

Here are the pics:

working flv to mp4 encoded file using the psp setting on format factory:
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non working flv to mp4 encoded file using generic mp4 for mobile setting in format factory:



EDIT - Upon further review it appears that there is one other difference I did not see. The top screen shot of gspot shows 24fps for the working file while the ones that don't work have a 18fps for some frickin reason. Oh well it looks like I will have to go back to the flvs and start over.

I don't see any benefit from converting the mp4s o mp4 with a different fps. I'm sure in the end the processing time required and the inevitable quality hit with the conversion will not make it worth while. I had wanted to avoid starting over but it looks like now I have no choice.

Oh well.

This post was worth while for seeing the two screen shots side to side and further evaluating what went wrong.

Perhaps if anyone has suggestions on audio batch conversion tools for mp4s it might help someone else in the future who has simpler corrections to make.

Thanks.