Max. Video Bit Rate For Matroska?

I recently bought a WD TV Live Plus. I use a Seagate Go 320GB USB drive. The drive has 37% free space and is regularly defragmented. The HDMI and USB cables are standards compliant and of high quality (Belkin). My HDTV is 720p.

I am experiencing problems mild to moderate stuttering during playback of large, high Bit rate, 1080p .mkv files. These are high quality, expertly encoded, dxva-compliant Matroska files. They play smoothly on a Seagate Freeagent Theatre Plus+ HD Media Player.

I have experienced this issue with Firmware 1.05.04_B and 1.06.16_B.

The frame rate of the files is fine (23.976 fps). According to MediaInfo, all other numbers are within spec.

So, I;m wondering what is the maximum video Bit rate, expressed in Mbps, that the WD Live supports?

DXVA-compliant?   What’s that mean?  

If that’s a reference to Direct-X Video Acceleration, that means nothing.   Only Microsoft cares about DXVA.  ;)

Last time I tried, I can watch the “Birds 50” MKV file, which is 50 megabits per second.

I didn’t go any higher than that, because that’s also the highest allowed by all commercial media, which is all I watch.

For your specific case, please post the full TEXT output of MEDIAINFO for such a file.

Thank you kindly for your quick reply and the offer of help. However, with respect, if you aren’t familiar with the relevance of DXVA-compliance to HD Media Players, then I think that you might not be the best person to assist me.

Rachael wrote:

if you aren’t familiar with the relevance of DXVA-compliance to HD Media Players…

Took about 15 minutes to read up on it.  I’m familiar enough with it to know that it’s completely irrelevant to any platform that doesn’t rely on Direct-X Video Acceleration…

… and an h.264 stream with more than 11 re-frames, would not be “DXVA-compliant”, whereas one with 11 or fewer, would be.

Since the chip only supports L4.1, you can only have 9 re-frames in 1280x720 and only 4 re-frames in 1920x1080… so that’s just one more reason why it’s meaningless to say the stream is “DXVA-compliant”… it has to be compliant with the chip’s decoding specs.

Many “DXVA-compliant” streams are simply incapable of being decoded by the Sigma 8654.

You have to be sending a supported stream to the 8654 if you want it decoded by the 8654, regardless of any “DXVA” specs.

That’s why we need to see the MediaInfo.  It’s a good bet that your “expertly encoded” files simply do not meet the device specs.

Hah.   Now that’s FUNNY.   Did a little more digging just to discover that “DXVA-Compliance” basically just means that the video is h.264 compliant and HP@4.1 or lower

In other words, someone had to come up with a cute little term to satisfy MICROSOFT Direct-X Acceleration limitations.

WD’s fully support compliant h.264 video up to these limits:  H.264 MP@L4.1 and HP@4.1 up to 1920x1080p24, 1920x1080i30, or 1280x720p60 resolution.

So if your video is “DXVA Compliant,” then the WD will play it.  It will also play a whole bunch more stuff that ISN’T DXVA compliant.

So, your question was…  ?

Oops…  RG beat me to the draw.

Oh, wait a sec, RG…

Are you saying that DXVA-Compliance could mean that it will play some videos that are NOT h.264 HP@L4.1 compliant?

Hmmm… odd for everyone to say that “DXVA = L4.1” on various forums.

Yes, anything that’s h.264 L4.1 should be “DXVA-compliant.”

But DXVA is just a specification for decoding h.264 video.  I find nothing in Microsoft’s specs for DXVA that says it’s limited to L4.1.  The 11 re-frame spec I mentioned doesn’t come from Microsoft, but from graphics cards.  You can have more re-frames and still be h.264- and DXVA-compliant.  The trick is whether it can be decoded by your hardware/software.

As far as I can see, in DXVA, there is support for up to 16 frames or 32 fields.

Microsoft does note:

“The initial design is intended to be sufficient for decoding the High, Main, and Baseline profiles. To support other profiles would require incorporating some additional features into the design”

and

“The 16-bit size of wMvBuffOffset means that for very large picture sizes (8192 or more macroblocks—that is, pictures larger than 1920x1080 HDTV), it is theoretically possible the decoder would need more than one data buffer per picture, because the H.264/AVC specification allows a worst-case average of 8 motion vectors per macroblock (8192 x 8 = 65,536).”

If DXVA supports more than 8192 macroblocks, then it supports more than L4.1, plain and simple. :wink:

RoofingGuy wrote:

You can have more re-frames and still be h.264- and DXVA-compliant.

Yeah, that’s the crux of my question.  The h.264 specifications list a max re-frame dependent on resolution.

And all the WDTV’s support up to that maximum (and in a lot of cases, can play more than the maximum allowed.)

So if someone “Out There” is saying that DXVA-compliant allows 11 re-frames in 1280x720, then that exceeds the h.264 standard.   The maximum according to standard for HP@L4.1 is 9.   So 11 would be a non-standard h.264 stream.

Sorry Tony… go back and check my edit:

RG wrote:
“The 16-bit size of wMvBuffOffset means that for very large picture sizes (8192 or more macroblocks—that is, pictures larger than 1920x1080 HDTV), it is theoretically possible the decoder would need more than one data buffer per picture, because the H.264/AVC specification allows a worst-case average of 8 motion vectors per macroblock (8192 x 8 = 65,536).”

 

If DXVA supports more than 8192 macroblocks, then it supports more than L4.1, plain and simple. :wink: 

L4.2 is 8,704 macroblocks and L5.0 is 22,080.

Looks to me, by the way I’m reading that, as if it’s up to the decoder whether to stop at L4.1 or not, but not set in stone in the actual specs that you can’t go past L4.1.

So, that makes me think you can go past L4.1 and still be “compliant”.

As far as I can see from posts dating back to 2009, Nvidia’s top-end cards would play L5.0/L5.1 files using DXVA acceleration, but ATI cards wouldn’t.  The ATI cards would only accelerate up to L4.1, and would play L5.0/L5.1 unaccelerated.  That was apparently a choice ATI had made with their drivers, to only provide one buffer per picture.

So, Nvidia also seemed to think a few years back that DXVA went past L4.1.

It may be precisely because ATI cards wouldn’t accelerate anything past L4.1 that since that time, post after post on forum after forum has said that “DXVA = L4.1”.  But I certainly can’t find Microsoft (or Nvidia) saying that.  As I said, it’s a decoder limitation, not a specification of the decoding itself.

Actually, thinking back on it… while trying to look up Microsoft’s specs, I was seeing in my search results that several pirate rips are now being labelled as “DXVA-compliant” – I hadn’t really seen that designation in the past.

Even though Direct X acceleration has absolutely nothing to do with hardware players, it could very well be precisely because many decoders (such as those ATI drivers and most hardware chips) don’t support levels past 4.1, and so many people have been encountering “won’t play” issues with their downloads, that the groups have started erroneously calling 4.1 files “DXVA-compliant”.  The rippers may have been getting complaints that their L5 rips were unplayable.

We’ll have to see what profile levels the OP’s “DXVA-compliant” encodes actually use – how the encoder is using the term.

TonyPh12345 wrote:

Last time I tried, I can watch the “Birds 50” MKV file, which is 50 megabits per second.

URL? Thanks.

Heh…  I’ve had those test files for so long I don’t remember where I got them.  

They’re probably out there on the net somewhere; it’s a whole bunch of files in M2TS and MKV format:

11/03/2010 11:31 AM 54,870,351 bird20.mkv
11/03/2010 11:33 AM 76,612,350 bird28.mkv
11/03/2010 11:33 AM 93,071,150 bird34.mkv
11/03/2010 11:33 AM 120,041,472 bird42.m2ts
11/03/2010 11:33 AM 153,521,171 bird55.mkv
11/03/2010 11:33 AM 202,389,504 bird70.m2ts
11/03/2010 11:33 AM 219,299,090 bird80.mkv
11/03/2010 11:34 AM 65,808,664 bird24.mkv
11/03/2010 11:34 AM 103,989,696 bird38.mkv
11/03/2010 11:34 AM 108,638,208 bird38.m2ts
11/03/2010 11:34 AM 114,918,832 bird42.mkv
11/03/2010 11:34 AM 140,559,134 bird50.mkv
11/03/2010 11:34 AM 146,817,024 bird50.m2ts
11/03/2010 11:34 AM 160,333,824 bird55.m2ts
11/03/2010 11:34 AM 167,019,983 bird60.mkv
11/03/2010 11:34 AM 174,422,016 bird60.m2ts
11/03/2010 11:34 AM 193,822,181 bird70.mkv
11/03/2010 11:34 AM 228,974,592 bird80.m2ts
11/03/2010 11:34 AM 242,133,511 bird90.mkv
11/03/2010 11:34 AM 252,801,024 bird90.m2ts

A quick google found this:

http://www.networkedmediatank.com/showthread.php?tid=27616