[Ffmpeg-devel] [BUG] slowness and/or memory leak with adpcm_ima_qt .mov files

Michael Niedermayer michaelni
Thu Feb 1 01:46:10 CET 2007


On Wed, Jan 31, 2007 at 04:28:12PM -0800, Allan Hsu wrote:
> On Jan 31, 2007, at 3:49 PM, Michael Niedermayer wrote:
> [...]
> >>I've run across what looks like a major memory leak caused by
> >>adpcm_ima_qt audio track decoding. ffmpeg output doesn't look out of
> >>the ordinary, but it is much slower than it should be (kind of slow
> >>on a PPC OS X machine, but *super slow* on a x86_64 linux machine).
> >>I've uploaded a sample to the FTP site as "shuffle-ima41.mov". Here
> >>is the ffmpeg output, killed because it was taking up too much  
> >>memory:
> >>
> >>./ffmpeg -i ~/Desktop/shuffle-ima41.mov -acodec pcm_s16le -vcodec
> >>mpeg4 -b 768k ~/Desktop/shuffle.avi
> >
> >does that also happen if you dont encode the video? -vn
> Interesting results. The following command line does not seem to leak  
> memory, but it doesn't ever seem to stop transcoding either:
> ./ffmpeg -i ~/Desktop/shuffle-ima41.mov -vn -b 768k -acodec pcm_s16le  
> ~/Desktop/shuffle.avi
> I stopped ffmpeg by hitting 'q' after it had written over 1.5GB of  
> data to shuffle.avi (the source movie is only 30 seconds long). I  
> tried to play back this file in VLC and the audio doesn't seem to  
> have survived. All I can hear is a periodic quiet clicking noise.
> >and what if you just copy the audio -acodec copy?
> I can't seem to find a muxer that will accept an adpcm_ima_qt stream.

-f null or crc, image2 should work too

> [...]
> Is there anything else I can do to help with this bug? As I mentioned  
> in the first email, I've already uploaded my sample file to the ftp.

sending a patch would help alot :)
also valgrind might be worth a try

ill look at the file of course if you noone else does and or sends a patch


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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