B. Bogart wrote:
Hey Etienne,
Just to chime in, I don't know the solution to your problem, but I've not heard of people using PDP at such a high-resolution.
.... other than the video decoding, it seems to perform very well.
Anyhow what comes out of your comments here is the fact that there is a size/decoding speed trade-off. I think your seeing the best options and I'd suggest going with the bigger files...
ya, ya, .... I've got two 5 gig scsi disks (RAID 0) running off a PCMCIA scsi card off a laptop ... so disk access speed is fine.
In the past (in jmax) I had a similar setup, reading raw component video (same frame size/rate).... with about 5% cpu. Big files, low compression, fast.
Tried the same tests with Gem? Any difference?
same kind of results for Gem.
although I encoded one video using mencoder .... forced ffmpeg mjpg as the codec. Mplayer plays it back with really low cpu (4% or something). Mplayer reports that it is using ffmpeg as the decoder.
when I try to open that same file in pix_film ... I get a message "ffmpeg: unsurported codec" .......wot? so pix_film is using a different version of ffmpeg? so I downloaded the latest ffmpeg and compiled it. No difference, pix_film still cant read it.
I got Gem from the demudi apt tree ..... does Gem come with its own version of ffmpeg statically linked inside it or something?
when people say that mjpeg is fast are they talking about avi ones or mov ones? ..... because xmovie decodes the libquicktime encoded mjpa files at the same speed as pd_qt
..............its all so god damn confusing.
Etienne
Good luck.
B>
PS: anyone put a wiki on pure-data.info about codecs?
etienne deleflie wrote:
Hi all,
I am in the throws of tetsing dozens and dozens of video codecs to find the one that is the most "right".
I want to decode 30 minutes of video (no sound) at 25fps (no dropped frames) at 640 x 280... from a 10gig scsi hard drive.... decoding must take up no more than around 30% CPU on a 2ghz processor (need the rest for audio)
codec must have no frame differenceing for fast access to sepcific frames... revers playback etc.
I'm using PDP .... which does yuv422 planar. ......
- mjpeg A (as encoded by transcode) chews 65% cpu
- mjpeg B (as encoded by Premiere) chews around 50% cpu
- component video (packed yuv422) chews around 30% cpu (acceptible) but
takes up too much hard drive space
- planar 4:2:0 is good ... its the closest ..... chews 25% cpu , takes
less hard drive than component but still too much hard drive.
theora is yuck, sorenson too much cpu, divx is small, fast and reasonable quality ....... but all these have frame differencing.
indeo 3 is poor quality but decode is very fast.... cant read indeo 4+ on linux (I think it is frame differencing anyway)
cinepak would do it, ..fast decode... but very poor quality.
.... any suggestions? ........... anyone found a mjpeg compressor that deocdes really fast?
does anyone know of a codec that is PLANAR .... but compresses each Y U and V plane? ..... something like that would be real fast for pdp.
etienne
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list