Issue of HW Transcoding Rotated Video

[020794 0]

Hi：

 

    I find a weird probelm of hw transcoding rotated video. All video with rotation 0 can be transcoded well and all video with rotation 90 or -90 are failed. 

 

   Then I did a test. I choosed one failed video with rotation 90, and set its rotation to 0 by exiftool manualy.  As expected, the failed video was hw transcoded normally.

 

   My server is intel nuc 7pjyh and os is ubuntu 18.04. The logs of the test were attached.

 

    

ffmpeg-transcode-7ade3475-3912-4033-b2df-d962bf76eba2.txt

ffmpeg-transcode-34fdd1dd-d86f-45a6-97b3-b938b0e85038.txt

[Luke 40104]

Hi, which ones are these logs from? Thanks.

[020794 0]

Hi, which ones are these logs from? Thanks.

 

The first log is about transcoding the video of rotation 90. (failed)

The second is about the video of rotation 0. (successful)

 

Thanks

[Luke 40104]

Ok, the first one isn't actually failing, it's just going too slow to be playable.

[020794 0]

Ok, the first one isn't actually failing, it's just going too slow to be playable.

 

You mean the hw transcoding was too slow to be playable? But why it could be transcoded well just by setting the video rotation tag to zero(which was proven by the second log)?  I'm confused with if there is substantive difference between them.

Edited October 2, 2018 by 020794

[020794 0]

I found the same issue was proposed by the nvenc user. https://devtalk.nvidia.com/default/topic/1028452/gpu-accelerated-libraries/unable-to-decode-amp-encode-a-file-with-cuvid-amp-nvenc/

 

Maybe it's a ffmpeg issue?

Edited October 2, 2018 by 020794

[Luke 40104]

ffmpeg is trying to autorotate, and that process is probably too slow for your machine to handle.

[020794 0]

ffmpeg is trying to autorotate, and that process is probably too slow for your machine to handle.

Thanks for your replies.

 

Could Emby add some option to disable auto scaling?

 

I think it will be helpful for those low end hardware with hw acceleration for NAS use typically.

Edited October 4, 2018 by 020794

[Luke 40104]

Yea it's possible. I think we just need to learn what other side effects that might bring.