[FFmpeg-devel] [PATCH] Lost VBR header

Michael Niedermayer michaelni at gmx.at
Sat Apr 16 16:36:54 CEST 2011

On Fri, Apr 15, 2011 at 12:19:32PM +0200, Peter Belkner wrote:
> Hi,
> FFmpeg is known for eating up the VBR header of MP3 files in case of  
> stream copy as e.g.
>    ffmpeg -i a.mp3 -acodec copy -y b.mp3
> The patch fixes this provided the "-acodec" switch is given in front of  
> the "-i" switch:
>    ffmpeg -acode copy -i a.mp3 -y b.mp3
> Apart from this subtility the patch should improve "libavformat.a" in  
> order that third party client code may copy MP3s without losing the VBR  
> header (as. e.g. my R128GAIN, see below).
> I really would apreciate if you could apply the patch or provide an  
> equivalent solution.

If the muxer simply generates a vbr header which should be quite
trivial for it to do (just counting packets and their sizes for
duration and buikding a simple index too)

not only would it be unneeded to preserve on stream copy but it would
be created even if the source file did not had one to begin with


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In a rich man's house there is no place to spit but his face.
-- Diogenes of Sinope
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