I'm having some playback issues when using ffmpeg and hevc_qsv codec. The video seems to convert fine, but playback has problems. When seeking in the video, e.g. clicking on the timeline bar in VLC, potplayer, or other player, the video takes a long time to seek. It takes about 10 seconds or so to seek. Once it starts playing again (after 10 seconds) it plays at twice the speed, like it is catching up. On Potplayer, it will also not display the preview thumbnails. Playing on VLC, it doesn't seek at all, it just stays in the same spot.
I have compiled most recent ffmpeg from scratch on Centos 7.2 using the newest 2017 SDK. I'm converting on a skylake cpu.
Converting with h264_qsv or libx265 the files are fine.
Using a simple command line:
/usr/local/bin/ffmpeg -ss 1437.664 -i /temp/lethal.mkv -c:v hevc_qsv -q 20 -load_plugins 6fadc791a0c2eb479ab6dcd5ea9da347 /temp/lethal-conv.mkv
I have uploaded an example file, but had to change the extension to mp3 to upload. So, change the extension back to mkv. I'm not sure if this is an ffmpeg problem or sdk problem.
Thanks for your report. In general, the FFmpeg wrappers for Media SDK are outside of the scope of this forum and issues/questions related to them should go to the FFmpeg mailing lists instead. One way to tell if an issue is in Media SDK instead of a layer above it is to experiment with the Media SDK samples or tutorials using raw (uncompressed) input for encode or a demuxed video elementary stream for transcode. In the experiments I've done I have not been able to replicate the issue you described with seeking on playback of HEVC output from Media SDK samples, which indicates there is a good chance that the issue is in the FFmpeg wrapper. Please let us know if you can see this problem with output from any Media SDK sample/tutorial.