RPI4 HW not transcode unsupported format yuv420p10 to supported format

[ahmadsans 0]

Hello,

I'm using Emby 4.6.0 on my Raspberry pi 4

I'm not sure why but when playing on emby android TV yuv420p10 is unsupported format and need transcode. Either H264 or HEVC, if the format  is yuv420p10, transcoding is needed. There's no need for transcoding if the format is yuv420.

is that correct behavior?

 

However, when transcoding with hw acceleration (ARM V4L2 H.264), the display show green screen. But it runs  fine when not using hw acceleration.
Since I use raspberry pi, I'd like to properly use hw encoding since rpi cpu is not enough for 1080p transcode.

From what I see in the log, when not using  hw transcode, the yuv420p10 is properly converted to yuv420 in the output. but when using hw transcode, the format is still yuv420p10 in the output which is not supported.

no hw transcode:

Output #0, segment, to '/var/lib/emby/transcoding-temp/F00FE3_%d.ts':
  Metadata:
    encoder         : Lavf58.35.100
    Stream #0:0: Video: h264 (libx264), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 23.98 fps, 90k tbn, 23.98 tbc (default)
    Metadata:
      encoder         : Lavc58.62.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 4672000/0/0 buffer size: 9344000 vbv_delay: N/A

with hw transcode:

Output #0, segment, to '/var/lib/emby/transcoding-temp/B94E08_%d.ts':
  Metadata:
    encoder         : Lavf58.35.100
    Stream #0:0: Video: h264 (h264_v4l2m2m) (High), yuv420p10le, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 4672 kb/s, 23.98 fps, 90k tbn, 23.98 tbc (default)
    Metadata:
      encoder         : Lavc58.62.100 h264_v4l2m2m

 

hardware_detection-63770604046.txt no-hw-transcode-log.txt hw-transcode-log.txt

[Luke 37008]

Hi there, did you explore the stats feature in the video player to learn why it was transcoding?

[ahmadsans 0]

The conversion reason in unsupported video profile.

I got the same reason for any video with yuv420p10 (Hi10P/10-bit) pixel format.
The player can play directly without transcoding when I re-encode the video into yuv420 (8-bit)

this is when using hardware acceleration:

 

this is when not se hardware acceleration

[ahmadsans 0]

I also found that when I try to convert, it failed to user hardware acceleration and fallback to software encoding.

it seems ffmpeg related, or my raspberry since manually compiled ffmpeg and ffmpeg from ubuntu repo also give similar error...

ffmpeg-transcode-4f01e56d-63d6-4489-b8de-7bef2908b23d_1.txt

[Luke 37008]

Did you follow our hardware acceleration setup guide?

https://support.emby.media/support/solutions/articles/44001160148-hardware-acceleration-overview