TRANSCODING -- Codec Speed vs. Application Speed

[GrayStrickland]

Do all apps transcode at the same speed, assuming other factors (codec, settings, source file) are the same?


I need to transcode about 40 files of 20-25 min each, because they won't play reliably on my Phillips DVP642. They're a mixture of Xvid 4 and Divx 5 (and all mp3) according to Gspot and Avicodec, so they should play fine in the 642, but they don't. The solution, I reckon, is to recopy them all using codecs and settings which are guaranteed to work in the 642. Thus, speed is a factor for this batch project. If app speed is pretty constant, assuming all other factors are constant, then I'll use the app that I like best. However, if some apps outpeform others in speed, even when source file, codec, settings, are the same, then I'll use what is fastest.

[guns1inger]

Try avirecomp. It has ben designed purely to convert files for playback on divx certified players. I believe it is a freebie, so try it n one and see if it works.

[celtic_druid]

If you aren't resizing or doing any filtering then the only thing an app could really do to effect speed is to change colourspaces. Anything decent will keep the entire process in the same colourspace (YV12). Other than that, it is basically all down to the codec/setting being used. The impact of changing colourspaces will be compounded if you are filtering or resizing since you will have more information to process (say 24bit RGB vs 12bit YV12).

[GrayStrickland]

Is "colourspace" another way of describing the size of the color pallette (total number of possible colors)?

[celtic_druid]

Not exactly. RGB and YUV are different ways of storing colour information.

http://en.wikipedia.org/wiki/YUV

Fact is that your source and output are YV12. So it is best to keep the entire process YV12. Doing otherwise will slow down encoding, which was the point I was trying to make. It also reduces quality.