GNOME Bugzilla – Bug 171796
PPC altivec optimizations cause green video images
Last modified: 2005-10-24 13:50:59 UTC
Distribution/Version: Ubuntu 5.04 (preview) When I attempt to play a particular video on my iBook (I've only tested the one video on it), the video output gradually turns more green before reverting to the normal colours every few seconds. There's also quite a lot of green replacing different hues in later sections of the video. It plays fine on x86. The particular video is "Spectrum Diamond", an Italian documentary on Matthew Smith, who wrote Manic Miner and Jet Set Willy for the ZX Spectrum. It's available here, but it's 402MB: http://zxvideos.speccy.cz/matt.avi I can't be sure how legal that is, although it seems that it was distributed by the producers for some time. Here's some links to screenshots (from Totem): Video starts, colours are normal: http://wired.st-and.ac.uk/~gingram/spectrum_diamond/gst-ffmpeg_normal_ppc.png A few seconds later, everything goes green: http://wired.st-and.ac.uk/~gingram/spectrum_diamond/gst-ffmpeg_green_ppc.png An example of more green artifacts later in the video: http://wired.st-and.ac.uk/~gingram/spectrum_diamond/gst-ffmpeg_more_green_artifacts.png #gstreamer IRC transcript, for the benefit of seb128: --- BBB | ggi, gst-ffmpeg 0.8.3 or .4? BBB | I've heard from some people that ffmpeg indeed has faulty PPC optimizations, i.e. they don't work... but that's an upstream bug, apparently... BBB | but I thought I disabled it in .4 (because of that) ggi | BBB: 0.8.4, from Ubuntu hoary. BBB | grmbl BBB | ok, then I failed to disable it BBB | ... :( ggi | BBB: Will I file a bug? BBB | Sure BBB | CC seb128@debian.org BBB | he maintains the ubuntu pkg, iirc ggi | BBB: Ok, doing so. ---
Sebastien, can you disable the PPC optimizations for now? I'll try to come up with a solution, it may be a build bug in gst-ffmpeg. I don't have a PPC so testing is hard, very hard.
right, I'll update gst-ffmpeg for that
As for the long-run, I'll need help from someone with ppc/altivec knowledge. I don't have the knowledge nor the machinery to extensively test/debug/fix this.
*** This bug has been marked as a duplicate of 319482 ***