[FFmpeg-user] AVI, WMV, FLV, MOV and MP4 to libx264 MP4 conversion bugs

[Lou]

On Sat, 5 Jan 2013 02:26:22 +0530
Teshan Nanayakkara <teshan87 at gmail.com> wrote:

> On Sat, Jan 5, 2013 at 1:31 AM, Lou <lou at lrcd.com> wrote:
> 
> > On Sat, 5 Jan 2013 00:53:21 +0530
> > Teshan Nanayakkara <teshan87 at gmail.com> wrote:
> >
> > > Hi there,
> > >
> > > I have used the following command line expression to compress and convert
> > > AVI, WMV, FLV, MOV and MP4 files to libx264 MP4.
> > >
> > > *ffmpeg -i abc.flv -vcodec libx264 -vf scale=-1:360 -qscale 7 -acodec
> > > libvo_aacenc -ab 32 -ar 24000 abc.mp4*
> > >
> > > To run this command I use PHP exec() function. I need to know the most
> > > appropriate and the correct commands to convert each and every (above
> > > mentioned) format to H.264 MP4 format without changing the aspect ratio
> > and
> > > video height less than or equal to 360 pixels. And with aac audio
> > encoding
> > > codec. Sometimes ffmpeg fails to convert above formats but not always. It
> > > may be depending on the source file's codecs. So I need to know how the
> > > above command should be modified to convert each video format mentioned
> > > above.
> > >
> > > Thanks
> >
> > The complete console outputs are missing. Without the ffmpeg commands
> > and console outputs we can only make guesses since "fails to convert"
> > is not as descriptive as any actual ffmpeg messages or errors.
> >
> > You should first run the ffmpeg commands manually, that is outside of
> > PHP, until you get a satisfactory result.
> >
> > Some other stuff:
> >
> > * libvo_aacenc isn't a great AAC encoder.
> >
> > * libx264 probably ignores qscale resulting in the default of "-crf
> >   24". This usually provides a decent output buy maybe not what you
> >   want.
> >
> > * "-ab" takes a value in bits, not kilobits, so use "-ab 32k".
> >
> > * "-ar 24000" seems unnecessary.
> >
> > * If the resulting width is an odd value then libx264 will complain
> >   with "height not divisible by 2". scale="trunc(oh*a*2)/2:360" should
> >   automatically round down to an even value if odd.