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Re: 720p video on G4?



On Sat, 2009-09-05 at 21:49 +0200, Rubén Gómez Antolí wrote: 
> 
> I'm trying to play a 1280x720 x264 video:
> 
> ------------- Video info -------------
> [mkv] Track ID 1: video (V_MPEG4/ISO/AVC), -vid 0
> [mkv] Track ID 2: audio (A_AC3), -aid 0, -alang eng
> [mkv] Will play video track 1.
> Matroska file format detected.
> VIDEO:  [avc1]  1280x720  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
> open: No such file or directory
> [MGA] Couldn't open: /dev/mga_vid
> open: No such file or directory
> [MGA] Couldn't open: /dev/mga_vid
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
> ==========================================================================
> ==========================================================================
> Opening audio decoder: [liba52] AC3 decoding with liba52
> Using AltiVec optimized IMDCT transform
> Checking for AltiVec resampler : 0x0000000a, 2
> Using AltiVec optimized resampler
> AUDIO: 48000 Hz, 2 ch, s16be, 384.0 kbit/25.00% (ratio: 48000->192000)
> Selected audio codec: [a52] afm: liba52 (AC3-liba52)
> ---------------- End of video info -----------
> 
> and I get frame drops: audio are in normal speed but video is slow and 
> delay.
> 
> This video could play in AMD Athlon 1500+ with 4+ years old, I think my 
> G4 is powerfull that it.

I'm afraid that while in theory the performance of these CPUs may be
about the same, in practise the Athlon machine still has several
advantages:

      * Due to x86 being more popular, its code is probably better
        optimized, in particular but possibly not only for the SIMD
        extensions. 
      * It probably has significantly more memory bandwidth, not only
        because it's a desktop vs. a laptop. 
      * ...

Also, the X driver version / configuration may also matter. Make sure
you're using xserver-xorg-video-radeon from sid and that the DRI is
enabled.

> Anyone can play 720p videos on Powerbook G4 or similar?

Some 'simpler' 720p videos play mostly fine on my PowerBook5,8 (very
similar to your PowerBook5,7), but not a chance for 'more complex' ones.
I assume 'simpler' vs. 'more complex' is a lot due to the bitrate of the
video, but there may be other factors.

> Do you think that compiling mplayer is a good option? Need a specific 
> library?

I doubt there's a lot to gain compared to mplayer-g4. IME sometimes a
video will play better in one player or the other, but it sounds like
you've already tried that.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer


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