Choppy video playback for H.264 60FPS content, but only in Windows

[Member2010]

This one's a bit of a puzzler. Computer is an older machine, (circa-2011 iMac with 2nd-generation i7 and Radeon HD 6970M + 16GB of memory and SSD storage) but still should be more than capable enough.

I have a particular video file created using PowerDirector (.m2ts container, H.264 video encoding) that simply refuses to play smoothly when in VLC on Windows, (similar results in MediaPlayer Classic Black, WMP, and other players) but renders flawlessly in VLC on OSX 10.11.

I've tried various different versions of the video driver, (15.201, 14.x, and one other) but the results are the same. Settings are pretty much stock inside of VLC too. Anybody ever run into something like it before?

The only "irregularity" about my setup (if you would call it that) is that Windows is installed natively in UEFI mode instead of legacy BIOS, which mandated fixing of the DSDT root bridge table for all hardware to work correctly (as is typical for Apple hardware of this era). I did have to disable the onboard graphics as well, in Device Manager. Every other workflow I perform seems to handle just fine (except for Windows's built-in screenrecorder, which refuses to function, and Edge, which required use of a flag to enable hardware acceleration). Graphically-heavy applications in particular (video editors, emulators, etc.) seem to work without trouble as well, performing generally identically to their counterparts in OSX. Even idle power usage measured by the UPS is the same.

Really out of ideas on this one. Task Manager shows hardly any resource utilization (I can't get it to display GPU use, at least in this build of Windows, so, a bit in the dark as far as that's concerned).

 

[tinygoblin]

AMD Radeon HD 6970M is fine for H.264. Forget VLC. Does your file play fine in mpv (use portable one if not using yet) with the following setup in mpv.conf?

vo=gpu
gpu-context=d3d11
hwdec=d3d11va
hwdec-codecs=h264,h264_qsv,hevc,hevc_qsv,vp8,vp9,av1,prores
profile=fast
deband=no
linear-downscaling=no

If it doesn't help, use mpv statistics (Shift+i) to get exact codec of you file and see if it's being processed by your GPU (should say (hwdec: d3d11va) in the end of Video line). If it isn't processed by GPU, use mpv --vd=help and find this codec's name in mpv, then add it in hwdec-codecs= line. Once you get it running with profile=fast, try profile=gpu-hq. You'll be good 100%!

P.S. Here's an example so you could have a better idea (don't mind low estimated fps on this example, it's because I skipped through the video):

 

[Member2010]

AMD Radeon HD 6970M is fine for H.264. Forget VLC. Does your file play fine in mpv (use portable one if not using yet) with the following setup in mpv.conf?

vo=gpu
gpu-context=d3d11
hwdec=d3d11va
hwdec-codecs=h264,h264_qsv,hevc,hevc_qsv,vp8,vp9,av1,prores
profile=fast
deband=no
linear-downscaling=no

If it doesn't help, use mpv statistics (Shift+i) to get exact codec of you file and see if it's being processed by your GPU (should say (hwdec: d3d11va) in the end of Video line). If it isn't processed by GPU, use mpv --vd=help and find this codec's name in mpv, then add it in hwdec-codecs= line. Once you get it running with profile=fast, try profile=gpu-hq. You'll be good 100%!

P.S. Here's an example so you could have a better idea (don't mind low estimated fps on this example, it's because I skipped through the video):

No better result with that program. It shows "hwdec: d3d11va," but drops a lot of frames on the output side (none on the decoder side). No change when using gpu-hq profile. Running it from the commandline yields occasional "audio device underrun detected" errors, although I'm not sure whether or not that's relevant.

Interesting wrinkle in this whole thing though: I tried forcing "hwdec" to "opengl," and the choppiness went away completely in MPV. Makes me wonder what would cause the D3D11VA decoding to perform so badly.