How to check if a 264 stream is DXVA compatible or not

[djesteban]

Hi guys,

How do I check if a 264 stream is DXVA compatible or not after encode? I know there's a tool called DXVAchecker, but I have no idea how to interpret its results. Is there another easy way?
Also, by comparing non-DXVA and DXVA encoder settings presets in meGUI, I cannot find the flag that tells whether I am creating a DXVA compatible file or not...

Thanks in advance for the help,
Cheers

[nurbs]

DXVAChecker checks what kind of DXVA your graphics card supports. It doesn't tell you anything about the files. Basically if your file doesn't exceed High Profile at Level 4.1 DXVA will work. Some cards can do even more than that. The wikipedia article about h.264 contains the restrictions. The main cause for incompatibility is probably that people use too many reference frames.

[djesteban]

DXVAChecker checks what kind of DXVA your graphics card supports. It doesn't tell you anything about the files. Basically if your file doesn't exceed High Profile at Level 4.1 DXVA will work. Some cards can do even more than that. The wikipedia article about h.264 contains the restrictions. The main cause for incompatibility is probably that people use too many reference frames.

All right, so this means that there's no specific flag for DXVA and that it's just a collection of specific settings that needs to be set... I did not know that
Thanks for your answer, I appreciate!

[djesteban]

Ohhh, also I found this on another site, anyone can confirm is this is true?

DXVA compliancy consists of three parts:
- The number of reference frames
- Macroblock options: no P4x4 blocks
- Maximum bitrate of 50000 kbit


The number of reference frames
***1080P Normal movie + Animation***
ref= 4 (max. resolution = 1920x1088) < 3 ref = not good enough for AHD
ref= 5 (max. resolution = 1920x864) < 3 ref = not good enough for AHD
ref= 6 (max. resolution = 1920x720) < 3 ref = not good enough for AHD

***720p Normal movie + Animation***
ref= 09 (max. resolution = 1280x720) < 5 ref = not good enough for AHD
ref= 10 (max. resolution = 1280x648) < 5 ref = not good enough for AHD
ref= 11 (max. resolution = 1280x588) < 5 ref = not good enough for AHD
ref= 12 (max. resolution = 1280x540) < 5 ref = not good enough for AHD

Macroblock options: no P4x4 blocks
- analyse=0x3:0x113 (anything else is either bad or not dxva compliant)

Maximum bitrate of 50000 kbit
- vbv_maxrate= (50000 max.)

When all these requirements are met, the encode is DXVA compliant.

[nurbs]

P4x4 doesn't matter as far as I know, but it's not that useful and deactivated by default anyway. VBV-Maxrate for High Profile should work with 62500. I have no idea what "3 ref = not good enough for AHD" is supposed to mean. Framerate is also important, but you won't run into trouble if your souce is DVD or blu-ray (unless you bob and keep the resolution too high).
Anyway as I said all of this is on wikipedia.

[djesteban]

P4x4 doesn't matter as far as I know, but it's not that useful and deactivated by default anyway. VBV-Maxrate for High Profile should work with 62500. I have no idea what "3 ref = not good enough for AHD" is supposed to mean. Framerate is also important, but you won't run into trouble if your souce is DVD or blu-ray (unless you bob and keep the resolution too high).
Anyway as I said all of this is on wikipedia.

Yeah, well, I've looked into the h264 wikipedia article, but I couldn't find any information about DXVA restriction... maybe you can point to the right section?
Thanks for your help by the way :)

[nurbs]

As I said the DXVA restriction is High Profile, Level 4.1.
There are tables with the limits for bitrate, framerate, features that can be used and there is a formula to calculate the maximum number of reference frames for arbitrary resolutions. There's even some x264 specific stuff right there in the article.