Hi Piers, Forgot to mention the grey bar is with H.261 (or other 352x288) transmitted streams. Cheers, Doug
> -----Original Message----- > From: Douglas Kosovic > Sent: Thursday, 6 March 2008 9:16 PM > To: Douglas Kosovic > Cc: Piers O'Hanlon > Subject: Re: [AG-TECH] Any more H.264 news? > > Hi Piers, > > Just wondering if you get the grey bar at the top of a 1/4 NTSC (i.e > shift-M) or NTSC (shift-L) video window? See attached PNG file (ignore > the blue mute, I don't have a camera to connect to my DVB PCI card at > home). It looks like the image is pushed down by the same number of > pixels as the bar. I seem to have that issue regardless of which > version of FFMpeg/SWScaler is used. > > I've reverted to ffmpeg svn -r 7110 and libswscale svn -r 21687 and VIC > doesn't crash in the MMX2 libswscaler code with i386 Fedora. I think I > might just disable the MMX2 code with a patch for the x86-64 build by > using a conditional in the RPM spec file for the time being. > > > Thanks, > Doug > > Douglas Kosovic wrote: > > Hi Piers, > > > >>> For Fedora 8 (i386 & x86-64), issue the following: > >>> yum update AccessGrid > >>> > >>> which will install the mpeg4/h264 services and a new version of > vic. > >>> > >>> Known issues: thumbnails for H.264 and MPEG-4 appear black, but > video > >>> windows are fine. This is because the software scaler that comes > with > >>> FFMpeg has been disabled to avoid a crash in some MMX2 assembly > code > >>> and > >>> the old vic scalar doesn't support the required colorspace. I > might > >>> have > >>> a newer version of vic released later in the week if I'm able to > >>> resolve > >>> the issue. > >>> > >> Thanks for sorting the RPMs out - > > > > Actually I haven't sorted the RPMs out yet, I wanted to use > > 'alternatives' mechanism to release several different VIC RPMs built > > with different build options, unfortunately there are issues when > > performing a rpm update from an older VIC rpm which doesn't use > > alternatives. The workaround is convoluted and involves RPM triggers. > > > > It might be for the better as more choices of VIC would only confuse > > things for users. > > > > > When do you see the crash occurring? > > > > With H.261 CIF video window as soon as I increase the window size, > > color-swscale crashes. > > > > If I do what one version of VLC I found does, which is disable the > > SWS_CPU_CAPS_MMX2 flag, see attached patch, it works for me. > > > > > It runs ok on my machines - I guess the snag may be compile-time > > > assembly optimisations...though at least some of it is runtime. > You > > > could try using a later version of ffmpeg - we just need to make > sure > > > its stable on all three platforms. > > > > I think it may have something to do with PIC addressing which > > subsequently results in the wrong register(s) being used with MMX2. > > > > I think I might try the Ubuntu ffmpeg patches ( > > ffmpeg_0.cvs20070307-5ubuntu6.diff.gz ) available here: > > http://archive.ubuntu.com/ubuntu/pool/main/f/ffmpeg/ > > which has -fPIC and assembly related patches. > > > > I've tried a few version of ffmpeg and libswscale (I made sure ffmpeg > > and libswcale had the same datestamps). > > > > When I mentioned I thought the Fedora 8 livna repository's ffmpeg was > > built with swscale in an email a few weeks ago, I was wrong, it isn't > > built with swscale. > > > > > > Cheers, > > Doug > >
