[FFmpeg-devel] Question regarding FLV Metadata patch dated 10 Sep, 2010

Michael Niedermayer michaelni at gmx.at
Thu Oct 6 03:24:11 CEST 2011

On Wed, Oct 05, 2011 at 11:11:18AM -0700, Pranav Desai wrote:
> Hello,
> I have a question regarding a patch that adds metadata to flv output.
> Here is the link to the patch
> http://git.videolan.org/?p=ffmpeg.git;a=commit;h=16f825085a53dc7241ef375e9bed9856435d4c16
> Actually I ran into an issue when transcoding Youtube videos. The input
> video has size 608x272 but after transcoding the size of the output video is
> 320x240, as it plays on youtube.
> After digging a bit further it looks like the metadata that is added by this
> patch adds the width and height as strings, so the Youtube player might not
> be able to read it and hence uses the default size. The video plays fine the
> only problem is that its squished into letterbox format because of the
> metadata.
> After remove the patch it seems to work just fine, the metadata looks fine
> and the size is also fine.
> For this test I used 'copy' codecs to eliminate all other possibility.
> I checked the metadata which is include below using flvlib (
> http://pypi.python.org/pypi/flvlib/0.1.5). The output is included below. The
> output shows that width and height are added as strings vs the original
> 'in.flv' file where its double.
> So I guess the question is, should it be adding only the metadata that is
> not already added like 'canseekontime' ? Because just above this patch in
> the code there are quite a few places that add the metadata like width,
> height,  audio/videodatarate, etc. so why add it again ?

its a bug indeed, ive just fixed it, thanks for the report

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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