[PD] gem codec basic review

Andrew Brouse brouse at music.mcgill.ca
Mon Dec 3 08:11:55 CET 2007

Hi Max,

JPEG decompression should be very fast on any modern CPU, it is however 
possible that at those frame sizes and 30 FPS, you may be seeing some 
jitter. If you are at 30 FPS, try reducing it to 15 or even 10 FPS and see 
what happens.



On Sun, 2 Dec 2007, Max Neupert wrote:

> Am 02.12.2007 um 16:35 schrieb Andrew Brouse:
>> If you want to do any scrubbing, varispeed or playing backwards of the
>> video, you need a CODEC which does not use temporal compression.
>> Photo-JPEG is in fact a very good choice in this case and if compressed at
>> 320 X 240 you get a good balance of file-size, picture quality and
>> processor load. JPEG 2000 should also be a good choice (supported by
>> QuickTime and there are libraries which support it on Linux but not sure
>> if it will play in GEM).
> hi andrew,
> i wonder if the photo-jpeg compression does introduce a jitter in the 
> decoding speed depending on the complexity of the content. gem would need a 
> different time to decode each time a different frame is called.
> i am working now with 1024x768 video compressed with 75% quality photojpeg 
> and sometimes see lags in the decoding.. but maybe it's just my imagination.
> max

More information about the Pd-list mailing list