2009-08-03 12:42:15     Improving libavcodec/libswscale decoding and conversion performance.

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2009-08-03 12:42:15     Improving libavcodec/libswscale decoding and conversion performance.

Marshall Seaborn (UNITED STATES)

Message: 78316   

 

I have an MPEG playblack application that runs under Blackfin uClinux on the BF548.  Currently, I'm getting roughly half-speed(it looks like slow motion) playback, i.e., a 32 second video clip plays back in about 50 seconds.  The video clip is an MPEG-4 Transport Stream file in standard definition (720x480) with video encoded at 2Mbps.

 

Can some one give me direction on how I might improve the playback performance so that my video plays back at speed?  I noticed that if I comment out the format conversion the playback executes at speed.  Any help is appreciated.

 

Thanks,

 

Marshall

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2009-08-11 23:54:46     Re: Improving libavcodec/libswscale decoding and conversion performance.

Mike Frysinger (UNITED STATES)

Message: 78700   

 

i dont know if you're trying to make a generic implementation, or you have some specific media you can control, but the obvious answers are to avoid conversions whenever possible.  that means transcoding on the fly from one format to another, or doing colorspace conversion from one source to match the hardware.

 

if you do need to do conversion on the fly, then try to restrict yourself to formats that have fixed point implementations as they will always be significantly faster.  if you do need to emulate floating point code, then try this page:

  docs.blackfin.uclinux.org/doku.php?id=optimization

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