Problem with 720p video playback (1 Viewer)

Rob99

Portal Member
September 12, 2010
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Hi!

I Have a problem playing 720p mkv x264 movies.
When playing movies with resolution 1280x720 (anamorphic), picture freezes.
Movies with resolution 1280x544 or similar works OK.
Also 720p TV shows works fine.

Could it be because of weak video card? Or is it codec fault?


MediaPortal Version: 1.1.1.0
MediaPortal Skin: Blue wide
Windows Version: XP
CPU Type: 3Ghz Pentium
HDD: 200+80+80GB
Memory: 1GB
Video Card: FX5200
Sound Card: SB Live
Remote: ATI Remote Wonder
TV: Panasonic 32''
TV - HTPC Connection: SCART
 

MageMinds

Portal Pro
January 29, 2007
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The picture freeze and the sound continue?

Anyways from your spec. I can tell you that your MP is not powerfull enough to decode 720p.

Maybe some 720p will work, but most won't. If you get the CoreAVC codec that might help you a little bit, since it's the most efficient codec around to decode x264, but it's not a magical receipe, the processor isn't powerfull enough to do the work.

A friend of mine have a similar CPU and I've installed a new video card, a nVidia GT240 SILENT with CUDA and CoreAVC codec it can play 1080p video at 25 mbits. The video card does all the hard work.
 

Rob99

Portal Member
September 12, 2010
8
0
Yes, picture freezes and sound continiues... And if you skip forward, then sound also stops.
And it's other way around - most 720p works. Only 3 out of about seventy 720p movies don't work. Others work perfectly with no PC overload.

And it's not only 1280x720 movies. One of them is 1008x544 and other 1280x544, so it couldn't be because of resolution.
Can't tell about all three, but two of movies that don't work was marked as anamorphic (really don't know what it means). Maybe that's the problem.
 

MageMinds

Portal Pro
January 29, 2007
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Anamorphic means that the picture is encoded using a different pixel height/width ration than the viewing ratio.

A DVD for example is encodec using the resolution 720x480, but this equals a ratio of 1.5 a 16/9 movie ratio is 1.77, so the raw image from the DVD is not formed correctly, the player have to adjust the display ratio to correctly show the picture. This is a way of encoding image to enhance the quality while respecting the format required by a certain media, in this case the DVD format that allow a maximum of 720x480. In 720p file we see that very little, you must have stumble on an odd file... Maybe it's an upscale from a DVD, so they kept the anamorphic.

Anyway maybe the anamorphic is too hard for your CPU to handle...

Trust me when I say your computer isn't fast enough to decode HD content ... you might get lucky with low bitrate 720p files, but some files have higher bitrate and you CPU won't be able to cope.

It's not the resolution the problem, it's the bitrate... You could find a file at 1080p with very low bitrate and your CPU would be able to get it and you could get a 480p file with really high bitrate that your CPU won't be able to decode. Everything is about the bitrate, not the size... I hear some say that the size will influence the bitrate, that's true, but the CPU doesn't care about how much pixel it have to generate, it care about how much information it have to compute each second... With your setup you could maybe decode 4 mbits files, then you get a file at 5 mbits and it freeze...

Look at the bitrate of movies that works and the bitrate of the movies that doesn't. Anamorphic, just add something the CPU have to do.
 

Rob99

Portal Member
September 12, 2010
8
0
Ok.
But bitrate also isn't answer.
Movies that don't work have: 747, 730, 332, 766 Kbps (Found another one, that doesn't work)
Some of the working movies: 745, 1001, 772, 618, 591 Kbps

And they all are Matroska mkv files.


And TV Shows with bitrate 3600 Kbps and above also work fine...
 

pilehave

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    Check the profile for the MKV's. Maybe the ones you have trouble with are high profile 5.1s? And the working ones lower profile 4.1 or so...
     

    Rob99

    Portal Member
    September 12, 2010
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    Working ones are 3.1, 4.0, 4.1, 5.1 and so on...
    The ones which don't work - one of them is 3.1 and other three are 4.0

    Mysterious :D
    Sometime, when I'll have more time, will try to compare working and not working files more closely... There must be a reason why those four refuses to work.
     

    MageMinds

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    January 29, 2007
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    Then I would suspect the file itself, which codec do you use?

    Would it be possible for us to see one of the file that doesn't work?
     

    MageMinds

    Portal Pro
    January 29, 2007
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    I suspect that those files uses evey trick in the x264 book to make it look "good" for that size...

    Man I would get the XviD before getting a 720p of 1h40 of 500 MB.

    My 720p movies are at least 4GB file size. Usenet is my friend man!

    Anyways, those trick in the book makes some codec to drop frames, codec maker doesn't integrate every little details of x264. Also SAF is not a codec, it's a codec pack ... I assume you're using ffdshow to decode your x264, IMO the worst possible codec to choose... Get your hand on CoreAVC for 10$ and you might get lucky and it will be able to decode those crappy files.

    There's no way I'm gonna download that, I fear my computer will hate me if I do... :) Not mentioning that this site also looks like a virus nest...

    Good luck!
     

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