BBC HD frame order judder

[Wilkoandout]

I often record BBC1 HD with a Hauppauge HVR 4400 and WinTV 7.0.30102. Up until recently, the transport streams played back perfectly in both software (I am using Cyberlink Power DVD, Smart Cutter, Nero and others), and on hardware (a Sony BDP S380). For hardware viewing I usually clean up the stream with TsRemux (and/or Smart Cutter), and then create a blu ray with multiAVCHD (which I think in turn uses tsMuxer), and burn to a Verbatim BD-RE with ImgBurn so I can watch in the lounge rather than on the PC.

Until recently the streams have played back perfectly witout fail on a Sony BDP S380, no problems at all. However, suddenly (June/July 2012) I am getting really bad judder. I have not changed any hardware. Using freeze frame on the BDP S380 it looks as though the frames are being played back out of order. In a pattern 8 frames long, the stream plays the 8th frame before the 7th, then resumes. So the frame order is 1 2 3 4 5 6 8 7 9 10 11 12 13 14 16 15 ... It does this for the whole file. In software on the PC the exact same streams are playing back no problem! Incredibly, a physical blu ray disc made this way plays fine on a PC with Cyberlink PowerDVD, but not in the Sony blu ray player! This has all suddenly started happening without any changes to hardware or software, having been okay for years up to now.

I know the BBC have been making changes to do with Wimbledon and the Olympics, and have boosted the resolution of BBC1 HD to 1080x1920, but I can't see why this would have any effect, but I suspect it is something to do with the BBC's encoders, since ITV HD and Channel 4 HD are still working fine just as before with no issues (and at 1080x1920). If it is something to do with the BBC changing their encoders, it is beyond my level of understanding to get any further.

I have tried creating the blu ray with multiAVCHD and also with Arcsoft Totalmedia Studio 3 (demo version). I have also tried cleaning the stream with VideoReDo H.264 v4.2 (demo) and TSDoctor (demo). I'd have bought one of these if they'd fixed it, but no effect. Same result every time - no trouble on the PC, frames not in the right order on the Sony!

Also I have tried using TsMuxer (and separately H264 level editor) to change the H.264 profile from 4.0 to 4.1, but that had no effect. Recoding the video with BD Rebuilder fixes the problem, but this takes a significant amount of time and there will be a loss of quality.

Is anyone out there seeing the same behaviour with BBC HD streams, and if so has anyone found a way to mend the stream to make the frames play back in the right order on a blu ray player without recoding the video?

[24673583]

Hi, friends.
Sorry, my English is not very good.
you need a software to repair the video stream，right?
Try to use this “DGIndexNV”

[Wilkoandout]

Originally Posted by 24673583

Hi, friends.
Sorry, my English is not very good.
you need a software to repair the video stream，right?
Try to use this “DGIndexNV”

Thanks for that. You will have to excuse my ignorance but I'm not very familiar with what a frameserver does, and/or how will it help. I can already decode, play and view the video stream on a PC, and I don't need to edit it. If a recode is required I can do that anyway with BD rebuilder (and this does fix the problem, since I have tried it, but a recode is what I'm trying to avoid).

[Wilkoandout]

Mystery solved: the BBC has changed to coding with 7 consecutive B frames separated by one i or p frame. You can see this if you open the files in avidemux or other software that gives the frame type. This explains the 8 frame judder pattern observed in the Sony player. The blu ray standard is no more than 3 consecutive B frames. I would like to thank wavelet from another forum for finding the answer, but sadly this means there is no way round other than to re-code or get lucky with a blu ray player that will play non-compliant files.

[mariner]

Greetings Wilkoandout. Interesting observation.

It appears my s185 handles 50i BBC contents differently: 50i files are played at 60p, while 50i BD at 50p.

Wonder if that's the case with the s380?

Many thanks and best regards

[Wilkoandout]

Good point mariner, and this could well be a factor. When I feed my s380 a stream from BBC1HD, it reports the playback as 1080/50p. 1080/50p is not blu ray standard. Sony added support for playback of 1080/50p in a firmware update in 2011 to enable compatibility with their camcorders, but it is highly unlikely that the BBC are transmitting this way.

I found the following article (http://www.bbc.co.uk/blogs/researchanddevelopment/2011/04/software-upgrade-for-bbc-hd-on.shtml) which suggests that the BBC are using 1080/25p, at least most of the time - and sometimes a mixture if i and p! Again, 1080/25i and 1080/24p are both blu ray standard, but not 1080/25p, and as you say, this could be another reason why the stream might not play properly off a blu ray disc.

The strange thing is that I have some older streams which I'm fairly confident are 1080/25i (by which I mean 50 fields per second interlaced into 25 frames per second), and although the S380 plays these older streams properly (less B frames), it still reports them as 1080/50p! I haven't yet figured out what software to use to find out for definite whether the streams or interlaced or progressive, but it seems possible that the S380 (which has latest firmware) is getting confused.

I'm certainly curious to find out whether these streams are i or p, but unfortunately, whether interlaced or progressive, 7 B frames in a row is almost certainly the root cause of the judder, as it exactly matches the observed pattern of the incorrect frame order, and is not blu ray standard. For the forseeable future it looks like a recode with x264 will be required.

[kieranrk]

Post a sample then.

[Wilkoandout]

Here's a short file sufficient to show the 7 B frames in a row.
https://docs.google.com/open?id=0B91gHVpnM-_tMjBXV0RQV2FVaTQ

[kieranrk]

Well it's MBAFF as usual, so it's neither interlaced nor progressive. It's likely that your playback device doesn't like the b-pyramid structures they are using.

[mariner]

Originally Posted by Wilkoandout

Good point mariner, and this could well be a factor. When I feed my s380 a stream from BBC1HD, it reports the playback as 1080/50p. ...

That should be the correct behavior.

Time to junk the s185.

[mariner]

It appears the s590 (US) also plays the 50i file at 60p.

[Wilkoandout]

Thanks mariner and kieranrk for looking into this. I'm going to admit defeat and recode with x264/bdrebuilder.