Slow VC1 transcoding

[Zarper 2]

When viewing VC1 movies in the Emby web client transcoding to h264 is slower then doing h264 to h264 transcoding. With h264 material my 4 core/thread CPU works at up to 300% and manages to transcode with veryfast preset (auto in Emby) with above 24 fps. But with VC1 material it doesn't hit 200% and the veryfast preset (still auto in Emby) is just short of 24 fps and I get pauses from time to time. I have to manually set the preset in Emby to superfast to get it to transcode fast enough.

 

FreeNAS 9:10

FreeBSD 10.3 jail

Emby 3.1.2 built from ports

[Luke 37046]

Hi @@Zarper, this can be normal i'm afraid. transcoding vc1 can be painful. Thanks for the info about the preset, I'll do some testing and see if we want the Auto setting to be smart about vc1. Thanks.

[Zarper 2]

Hi @@Zarper, this can be normal i'm afraid. transcoding vc1 can be painful. Thanks for the info about the preset, I'll do some testing and see if we want the Auto setting to be smart about vc1. Thanks.

I understand that vc1 might be a bit slower, but should it not decode fast enough to allow the encoding to saturate more of the CPU?

 

Anyway, it would be nice if I could keep it at auto and not have to worry about it stuttering. So thank you for looking in to it.

[Luke 37046]

I understand that vc1 might be a bit slower, but should it not decode fast enough to allow the encoding to saturate more of the CPU?

 

Perhaps the vc1 decoder support for multi-threading is not quite as good as h264.