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+---- Thread: [AppleTV] Broadcom Crystal HD stuttering playback on Apple TV? (/showthread.php?tid=67526)
- dan1son - 2010-03-31
I actually sat down to use my ATV with CrystalHD card (Ubuntu karmic 9.10 with XBMC SVN:28256MS... I build my own) to watch a movie with the wife just the other night. We tend to use the Revo on the TV downstairs, but had some guests staying at the house consuming that one.
We watched a 2~ hour 1080p movie (Adventureland) which clocks in at just under 15gigs with an overall bitrate of 18.2mbps. It would have the occasional SetDropState 0, 1, 0, 1 which was accompanied by rapid hard drive noise... maybe every 15-45 minutes. It'd be easily fixed with a simple pause/resume.
The files are stored on my linux server using NFS.
Figured I'd share a success story. The setup is amazing and many thanks go out to Davilla for his fantastic work. I'd have never thought my ATV would be so useful again.
- deltazulu - 2010-03-31
To all: I was having the stuttering playback issue on some 720p content and all 1080p content, even with the CrystalHD selected... Then I found that I had the AppleTV OS set to 1080p in the Audio & Video settings for TV Resolution, and XBMC was trying to run at an odd resolution of 1280x1024. I thought that resolution didn't seem right and remember reading on the forum that the AppleTV OS limits decoding to 720p, so I figured I would set the AppleTV OS to 720p and see if that helped. Sure enough, now 720p and even 1080p playback is butter smooth. There are a few glitches here and there with some of my 1080p stuff, but 90% of it is just great.
Would be nice if someone else can test this -- just a theory as to why some of you are having some bad 1080p playback.
- frumpy_uk - 2010-03-31
dan1son Wrote:I actually sat down to use my ATV with CrystalHD card (Ubuntu karmic 9.10 with XBMC SVN:28256MS... I build my own) to watch a movie with the wife just the other night. We tend to use the Revo on the TV downstairs, but had some guests staying at the house consuming that one.
We watched a 2~ hour 1080p movie (Adventureland) which clocks in at just under 15gigs with an overall bitrate of 18.2mbps. It would have the occasional SetDropState 0, 1, 0, 1 which was accompanied by rapid hard drive noise... maybe every 15-45 minutes. It'd be easily fixed with a simple pause/resume.
The files are stored on my linux server using NFS.
Figured I'd share a success story. The setup is amazing and many thanks go out to Davilla for his fantastic work. I'd have never thought my ATV would be so useful again.
Good man. I don't have the wherewithall to get linux running on my aTV but I'm also delighted with what this little box is doing thanks to davilla (and the team).
- Riderzzz - 2010-03-31
deltazulu Wrote:To all: I was having the stuttering playback issue on some 720p content and all 1080p content, even with the CrystalHD selected... Then I found that I had the AppleTV OS set to 1080p in the Audio & Video settings for TV Resolution, and XBMC was trying to run at an odd resolution of 1280x1024. I thought that resolution didn't seem right and remember reading on the forum that the AppleTV OS limits decoding to 720p, so I figured I would set the AppleTV OS to 720p and see if that helped. Sure enough, now 720p and even 1080p playback is butter smooth. There are a few glitches here and there with some of my 1080p stuff, but 90% of it is just great.
Would be nice if someone else can test this -- just a theory as to why some of you are having some bad 1080p playback.
I never touched the apple's frontrow display settings. it was standing always on 1080p. Now testing out when setting it to 720p and i have already some improvement. (mainly for my 720p movies)
i didnt have to problem with the odd resolution before, always on 720 output in xbmc-settings)
Is the any need for posting the differences with the xbmc.logs from 720p and 1080p from frontrow settings? Or is this not relevant for crystalHD support?
- interceptor121 - 2010-04-01
deltazulu Wrote:To all: I was having the stuttering playback issue on some 720p content and all 1080p content, even with the CrystalHD selected... Then I found that I had the AppleTV OS set to 1080p in the Audio & Video settings for TV Resolution, and XBMC was trying to run at an odd resolution of 1280x1024. I thought that resolution didn't seem right and remember reading on the forum that the AppleTV OS limits decoding to 720p, so I figured I would set the AppleTV OS to 720p and see if that helped. Sure enough, now 720p and even 1080p playback is butter smooth. There are a few glitches here and there with some of my 1080p stuff, but 90% of it is just great.
Would be nice if someone else can test this -- just a theory as to why some of you are having some bad 1080p playback.
The 1280*1024 come from your TV not able to display 1080p I have the same on my HD Ready TV set if I set it to 1080i however it makes no difference in terms of dropped frames, you just have to set correct values for overscan. If 1280*1024 is the max resolution of your panel there is no point getting 1080p content as it will go through double scaling process and look worse than 720p
- noggin - 2010-04-04
davilla Wrote:I don't understand this 1440x800 size for encoding, it's not 1080p nor 720p. Why the odd size? Anyway, try r27557 or beyond. If that does not help, I'd like to see an xbmc.log from playing one of these.
I think I know the reason for 1440x800.
A number of broadcasters in Europe (and the US on satellite and cable as well I believe) use 1440x1080 16:9 rather than 1920x1080 16:9 for their H264 HDTV standard. (BBC HD and ITV1 HD in the UK do).
This is partially because a couple of the major HD video tape formats used for location shooting single-camera documentaries and drama (HD Cam and DVC Pro HD) are 1440x1080 subsampled on tape/flash - so if you shoot mostly on these formats, you will have no reason to broadcast a 1920x1080 image (as there will be no >1440 resolution present in your source material)
This means that their HD DVB broadcasts are 1440x1080 non-square pixel, rather than 1920x1080 square-pixel.
If the source is a wider than 16:9 movie, then this is likely to be letterboxed, which could mean you end up with a 1440x800 non-square pixel active picture area (with the other 280 lines of the 1440x1080 signal containing black)
If you're re-encoding this then you could resample to 1920x800 square pixels, cropping the black bars and resampling to square pixels, but there is no real point, as there will be no horizontal detail >1440 pixels per line. It may be simpler and quicker just to crop the 280 lines and keep the non-square pixels to deliver a 1440x800 image.
My bet is that the 1440x800 file is a letterboxed movie sourced from a 1440x1080 HD broadcaster.
Square pixels are a pretty PC-centric concept.
SD digital broadcast video (4:3 and 16:9) has always been non-square (702x576 is the 50Hz 4:3/16:9 image area, with a slightly wider digital 720x576 frame to avoid clipping. Knowing your pixel aspect ratio is just as important as knowing your image dimensions!), and 16:9 1440x1080, 1080x1080 and 960x720 non-square are all used in various production formats, alongside 1280x720 and 1920x1080.
(I used to work on broadcast video SD and HD hardware back in the day - and remember the powerful concept of "pixel/sample aspect ratio" being explained to me, and the realisation that the pixel dimensions of an image are meaningless in display terms if you don't know the pixel aspect ratio, and assuming 1:1 pixel aspect ratio is not a good idea in the video world.)
- Gurney - 2010-04-12
Hello all,
Which revision of XBMC is the best for an Apple TV under Hardy (minimal) with the Broadcom chip?
I am running 28256 (latest in the repos) and I am having quite some troubles for playbacking my 1080p content.
It may as well come from the codecs but before re-encoding everything I want to make sure it is not a SVN issue
Also, any place where I could find information on the recommended codecs/settings for encoding for playback on a ATV+BCM?
Thanks a lot !
- konan - 2010-04-13
Gurney Wrote:Which revision of XBMC is the best for an Apple TV under Hardy (minimal) with the Broadcom chip?
I am running 28256 (latest in the repos) and I am having quite some troubles for playbacking my 1080p content.
Thanks a lot !
The r28256 is the latest available from the mirror that considered relatively stable until the merge is complete. You should not expect from the development release to not have errors since it's in the development and not the final release. Instead try to find ways to overcome problems or at least report the behavior in order for the developers to be aware of what to look at.
- Olethros - 2010-04-17
noggin Wrote:I think I know the reason for 1440x800.
A number of broadcasters in Europe (and the US on satellite and cable as well I believe) use 1440x1080 16:9 rather than 1920x1080 16:9 for their H264 HDTV standard. (BBC HD and ITV1 HD in the UK do).
This is partially because a couple of the major HD video tape formats used for location shooting single-camera documentaries and drama (HD Cam and DVC Pro HD) are 1440x1080 subsampled on tape/flash - so if you shoot mostly on these formats, you will have no reason to broadcast a 1920x1080 image (as there will be no >1440 resolution present in your source material)
This means that their HD DVB broadcasts are 1440x1080 non-square pixel, rather than 1920x1080 square-pixel.
If the source is a wider than 16:9 movie, then this is likely to be letterboxed, which could mean you end up with a 1440x800 non-square pixel active picture area (with the other 280 lines of the 1440x1080 signal containing black)
If you're re-encoding this then you could resample to 1920x800 square pixels, cropping the black bars and resampling to square pixels, but there is no real point, as there will be no horizontal detail >1440 pixels per line. It may be simpler and quicker just to crop the 280 lines and keep the non-square pixels to deliver a 1440x800 image.
My bet is that the 1440x800 file is a letterboxed movie sourced from a 1440x1080 HD broadcaster.
You are pretty much right - I asked the original uploader and they confirmed the original source was 1440x1080 broadcast. This was cropped and re-encoded before it was uploaded.
- sabath - 2010-04-18
hi
im new here
I have apple tv with broadcom hd.
I found that it plays well with FPS around 30 and shatters with higher. All those videos with 720p and FPS=60 imposible to watch
I have installed christalhd 26 and last xbmc r28256
- interceptor121 - 2010-04-18
sabath Wrote:hi
im new here
I have apple tv with broadcom hd.
I found that it plays well with FPS around 30 and shatters with higher. All those videos with 720p and FPS=60 imposible to watch
I have installed christalhd 26 and last xbmc r28256
There is a known problem with interlaced content other than that any progressive scan at 720p plays perfect
1080p plays okish until [email protected] no chance at present for level5 and higher
Currently AppleTv only displays 720p so even if you play a 1080p it gets decoded, donwscaled and the re-upscaled. So 1080p should not look any better than 720p
Hoping that Davilla finds the issue with 1080p and that 1080p bluray content improved as now few frames are dropped the content remains watchable though
- sabath - 2010-04-19
interceptor121 Wrote:There is a known problem with interlaced content other than that any progressive scan at 720p plays perfect
1080p plays okish until [email protected] no chance at present for level5 and higher
Currently AppleTv only displays 720p so even if you play a 1080p it gets decoded, donwscaled and the re-upscaled. So 1080p should not look any better than 720p
Hoping that Davilla finds the issue with 1080p and that 1080p bluray content improved as now few frames are dropped the content remains watchable though
Actually Im speaking about 720p
Im not a big pro in all this formats. I just noted that 60 FPS video can't be played.
By the way my MacBook Pro 3.1 also have a lot of troubles while playing back those 60 FPS 720p videos
- interceptor121 - 2010-04-19
60 fps is interlaced check the media info so 720 or 1080 if it is interlaced you have a problem
- sabath - 2010-04-19
interceptor121 Wrote:60 fps is interlaced check the media info so 720 or 1080 if it is interlaced you have a problemsorry for stupid question but how to know whether it interlaced or not
and why interlaces can't be play backed with Broadcom HD?
- davilla - 2010-04-19
interceptor121 Wrote:60 fps is interlaced check the media info so 720 or 1080 if it is interlaced you have a problem
Not 720p@60, this is really progressive at 60 fps and is usually found in the USA as one format of ATSC (QAM/off-the-air) broadcasts. 1080i@30 is the other dominant ATSC format but 720p@60 is more widely used. The HD-PVR captures 720p@60 from component with h.264 compression.