How to convert .VOB to mp4 using ffmpeg?

sarbojit · 05-11-2011, 07:34 AM

Hi,
I am looking for an option to convert .vob file to mp4 format. Command "ffmpeg -i S.vob x.mp4" is giving error message "[libfaac @ 01cac110] Unable to load libfaac.dll". I tried to convert in other formats like .avi with the same command and got success.
Conversion is decreasing the quality like hell. Though size of the file after conversion is as big as original then why this bad quality. Some where I have read if I will not specify any argument it will keep the quality same but here it is not happening. Not sure why.....
Any input will be highly appreciable.

rylan76 · 05-11-2011, 08:18 AM

Sounds like you've got some missing DLLs needed by ffmpeg?

Not sure if it will help, but try MPlayer. At least under Linux, its got a real -good- encoder called mencoder that comes along with it that should be able to do this easily.

However, as AFAIK mplayer uses some FFPMEG components (on Linux it uses some libraries, .a and .so files which are there if you've compiled FFMPEG before installing mplayer) so I'm not sure if you go and get it on Windows (there IS an mplayer for windows, AFAIK) it will include mencoder, and if / how its codecs will work.

pwalden · 05-12-2011, 11:10 AM

It could also be that the ffmpeg version you have was compiled without faac libraries. For example, this is the case in Fedora/RPMFusion. You could download the source and recompile with faac support.

Alternatively, you could specify something other that AAC audio encoder. I believe AC3 is still mp4 compliant. Try AC3 by adding a -acodec ac3 argument to force use of AC3 audio encoder.

The mplayer site has a document on mp4 conversions. I think that mencoder/ffmpeg don't really support the mp4 container, and a subsequent muxer is needed to convert the output to mp4.

Another option is h264enc, it's a sophisticated shell around mencoder and other tools to generate high quality mp4 files. Typically it uses non-ffmpeg tools to convert intermediate mencoder avi file to mp4 with AAC audio. To get AAC you will need faac command installed. h264enc has a neat checker that reports on the readiness of your system for conversions.

Here is an example from my Fedora 14 system (Note: that mencoder/ffmpeg lacks AAC support, but faac and MP4Box are installed to provide AAC and mp4 conversions):

Code:

[pwalden@walden8 ~]$ h264enc -sc

-> Checking for 'MPlayer'..................... OK
-> Checking for 'MEncoder'.................... OK
-> H.264 video support in MEncoder............ YES
-> AAC (FAAC) audio support in MEncoder....... NO
-> MP3 (LAME) audio support in MEncoder....... YES
-> AC3 (lavc) audio support in MEncoder....... YES
-> PCM audio support in MEncoder.............. YES

-> Checking for 'bc'.......................... OK
-> Checking for 'pv'.......................... FAILED! [no support for DVD ISO dumps]
-> Checking for 'dd'.......................... OK
-> Checking for 'neroAacEnc'.................. FAILED! [no support for AAC+ audio]
-> Checking for 'aacplusenc'.................. FAILED! [no support for AAC+ audio]
-> Checking for 'oggenc'...................... OK
-> Checking for 'flac'........................ OK
-> Checking for 'faac'........................ OK
-> Checking for 'less'........................ OK
-> Checking for 'lsdvd'....................... OK
-> Checking for 'dvdxchap' (from ogmtools).... FAILED! [no support for DVD chapters export]
-> Checking for 'mkvmerge' (from mkvtoolnix).. FAILED! [no support for the MKV container]
-> Checking for 'ogmmerge' (from ogmtools).... FAILED! [no support for the OGM container]
-> Checking for 'MP4Box' (from gpac).......... OK
-> Checking for 'tsMuxeR'..................... FAILED! [no support for the TS container]

If you have installed a required program but the script
can't find it, run 'h264enc -r' to reset the config file.