My PowerMac G5 Quad 2.5 GHz/NVIDIA GeForce 7800GT has almost no problems playing 1080p QT files downloaded from Apple or 720p or 1080i TS files from US broadcast HDTV, but I can't find a way to play BBC HD TS files. I pulled down a copy of the BBC's Torchwood in 1080i/H264.DD5.1 and my poor G5 Quad is struggling mightily to play it.

VLC 0.8.5 fails completely with just a grey screen, while v0.8.6-test1 gets me about 1 second of good video (more if there's not much action in the frame) before it stops on a single frame with the audio continuing in the background. Hitting pause then play gets me another second of good video before it goes falls back to still frame with continung audio. MPlayer OSX v1.0pre9 is probably the best of the bunch as the video doesn't stop, but there are so many skipped frames as to make it unwatchable.

So, has anybody been able to successfully play BBC HDTV TS files on their PowerMac G5, or is this just something which is too much even for my almost-new G5? Also, what's so difficult with the BBC 1080i transport streams which I cannot play compared to the Apple 1080p QT files which don't give me any problems?

Any help or information would be much appreciated.

Well, what are the video bit rates for the various samples you are comparing?

The BBC HD stream for Torchwood is around 20 Mbit/s, while Apple's HDTV files are around 10 Mbit/s which clearly answers why the BBC files are straining my system. Any suggestions for a method to play these high bitrate files, or are they just too much for a G5 Quad?

The BBC HD stream for Torchwood is around 20 Mbit/s, while Apple's HDTV files are around 10 Mbit/s which clearly answers why the BBC files are straining my system. Any suggestions for a method to play these high bitrate files, or are they just too much for a G5 Quad?

Do you record BBC HD content from Freeview or satellite, and what hardware/software are you using?

I don't believe it's the bitrate that's causing the problems since most 1080i broadcasts in the states approach 19mb/s. That depends on the broadcaster, but that's the ideal in any case. My dual G5 powermac w/ a radeon 9800 plays 1080i files just fine. Since your G5 is more powerful than mine, I can't see the bit rate as an issue. It must be how the BBC is encoding the files and maybe how you're acquiring them.

I don't believe it's the bitrate that's causing the problems since most 1080i broadcasts in the states approach 19mb/s. 1080i broadcasts in the states are MPEG2 encoded material. The BBC sample in question is encoded with H.264 which is much more resource intensive when decoding than MPEG2.
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The main reason you are having problems with the BBC-HD clips is that they use MBAFF while SKY-HD uses PAFF. MBAFF needs a lot more CPU power to decode.

Even the fastest Core 2 Duo also have some problems with these unless you use coreavc and halli split. The newer graphics cards and NVidia Pure Video seem to handle these a little better.

The main reason you are having problems with the BBC-HD clips is that they use MBAFF while SKY-HD uses PAFF. Those are some impressive acronyms, but nobody mentioned Sky-HD.
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Those are some impressive acronyms, but nobody mentioned Sky-HD.
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I just mentioned it because they both use h.264 encoding but they required completely different playback power even though SkyHD is using a lot more bitrate they still require less CPU power to decode than the lower rate BBC clips that use MBAFF.

CoreAVC played back BBC's 1080i almost flawlessly for me on my bottom end Core 2 Duo. There were a couple of stutters, but overall it was extremely impressive. On my 6700 (2.6GHz) C2D machine, it decodes without any stutters whatsoever.

Your suggestion that a newer graphics card might help are intriguing. I'd certainly replace the G5 Quad's Nvidia GeForce 7800GT with the new ATI Radeon X1900 G5 Mac Edition if I knew that it would work. The ATI web site for this card pushes its use for games and graphics apps, but glosses over its use to improve HDTV playback. The Torchwood TS files are 1080i, H265, DD5.1 and at about 45 minutes per episode are around 7 Gb each and I've still been unable to find any program which can play them back without many skipped frames. Has anybody tried the new ATI card for HD playback to see if it helps?

There is nothing that will play BBC-HD files on the Mac OS X. Heck, there's almost nothing that will play them on the PC. On a Core 2 Duo PC, CoreAVC and Halli split is the only thing that will play them and then some of those are somewhat jerky.

The hardware acceleration of mpeg 2 or mpeg4 (h.264) HD files was never never enabled on any of the Mac ATI or Nvidia cards.

I did some more research on the ATI Radeon X1900 this morning and according to BareFeats <http://www.barefeats.com/quad15.html> it's no better, and in some cases worse than the Nvidia GeForce 7800 which came with my G5 Quad. It's only really of interest to people who bought their G5 with the low end NVidia GeForce 600. BareFeats only covers game specs, but if there's no h.264 hardware acceleration in the new ATI card then it's clearly not going to help me with my BBC HD files.

Given that there's no current solution using my G5 Quad as the playback device, does anybody have experience with the Zensonic media player (or something similar) currently on Power Buy at <http://www.avsforum.com/avs-vb/forumdisplay.php?f=66>? I'm thinking I could move the TS files from my G5 to the Zensonic via a portable USB2 drive, or maybe even using 100 BaseT networking. I thought a PS3 might work, but it's media player functionality is limited to a lot fewer formats than the Zensonic.

Hi there I just got this file IMAX.SPEED.WMV-HD.1080P.DTS.Fanxy@Silu.avi and I can play it... but... it plays 4:3 ???????? why the hell?

Try using FFMpegX to convert to avi files which will then playback in either QT with Perian or VLC.

IMAX films are 4:3 aspect ratio.

Try using FFMpegX to convert to avi files which will then playback in either QT with Perian or VLC.

I tried using FFMpegX to convert to a lower bitrate AVI for playback on my Quad G5, but the output file was hugely distorted with just fragments of the original video fleetingly visible in a few, scattered frames. FFMpegX appeared to correctly identify the original file (as MPEG-TS, h264, yuv420p, 1440x1080), but the Progress Viewer reported lots of errors during encoding (mostly "top block unavailable for requested intra mode" and "error while decoding").

My guess is the BBC is using a form of h264 which FFMpegX doesn't fully recognize, but I'm using the latest version (0.0.9x r2) so there's not much I can do until a new version is released. Does anybody know of of any other transcoding programs out there which can handle BBC h264 files?