[FFmpeg-user] [Bulk] Muxer Catch-22 with '-target pal-dvd'

[Francois Visagie]

> -----Original Message-----
> From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> bounces at ffmpeg.org] On Behalf Of Tim Nicholson
> Sent: 07 May 2013 11:05
> To: FFmpeg user questions
> Subject: Re: [FFmpeg-user] [Bulk] Muxer Catch-22 with '-target pal-dvd'
> 
> On 05/04/13 10:17, Francois Visagie wrote:
> > Hi All,
> >
> >
> >
> > Just a heads-up for the odd DVD being authored in SD resolution still,
> > there's a Catch-22 with the '-target pal-dvd' option.
> >
> >
> >
> > When encoding without that option, the (grantedly intermediate) output
> > file's audio cannot be played by some DirectShow applications like
> > Windows Media Player (see ticket 1720
> > <https://ffmpeg.org/trac/ffmpeg/ticket/1720>
> > ).
> >
> >
> >
> > The work-around is to apply '-target pal-dvd'.
> >
> >
> >
> > However, when encoding 704-wide Rec.601 source like DV (perfectly
> > legal resolution for DVD), this option causes distortion by forcing
> > horizontal resolution to 720 pixels (see ticket 2434
> > <https://ffmpeg.org/trac/ffmpeg/ticket/2434> ). Some background on
> > Rec.601 sources and 704-pixel horizontal resolution at
> > http://en.wikipedia.org/wiki/Pixel_aspect_ratio.
> >
> >
> >
> > The work-around in this case is _not_ to use '-target pal-dvd' but to
> > specify the DVD-compliant encode using individual options, e.g.
> >
> > '-codec:a ac3 -b:a 128000 -codec:v mpeg2video -g 15 -bf 2 -bufsize
> > 1835000 -b:v 6090000 -maxrate 9800000 -muxrate 10080000'.
> >
> 
> It is easier to still specify -target pal-dvd then afterwards overide the
size
> with -s 704x576.

That's an interesting suggestion, thanks. It would need to somehow go into
my standard encode Windows batch process (used for both 720x576 as well as
704x576 encodes). It would need to determine at runtime when input is
704x576 and only specify the resize then. Could something like ffprobe be
used for this detection in a batch file (my ffmpeg build came without it)?

Also, I'm not familiar with the resizer's behaviour; would it still perform
an unwanted resize when the source is already at 704x576?

> 
> >
> >
> > In this case the output file's audio won't be playable by Windows
> > Media Player and similar and can't be demuxed by e.g. Avidemux for
> authoring.
> > Work-arounds are remuxing the output in another application, and/or
> > using another player like Media Player Classic, and/or demuxing for
> > authoring with ffmpeg itself or another application.
> >
> >
> >
> > Cheers,
> >
> > Francois
> > [...]
> 
> 
> --
> Tim
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