codec 422 support

High 4:2:2 Profile - as an extension of Hi10p profile - is not supported by Amlogic HW decoder (nor any known cosumer HW decoder AFAIK), it has to be software-decoded. S905 may be not powerful enough to do software decoding of 1080p 4:2:2 video.

Fallback to software decoding for High 4:2:2 profile is already covered in my development builds: projects/S*05: add more unsupported H264 encodings to HW decoding bla… · kszaq/LibreELEC.tv@448424a · GitHub

To sum up, you are not able to play 1080p High 4:2:2 videos with S905.

4:2:2 H264 is software decode-only on pretty much every consumer platform (including x86). I have a Haswell i5 NUC that can do a reasonable job with 1080i25 (aka 1080/50i) 4:2:2 H264 at 38Mbs including a YADIF 2x deinterlace. (It used to struggle until ffmpeg improvements in H264 multithreading were made)

Quoting Wiki:

Quote

High 4:2:2 Profile (Hi422P, 122) Primarily targeting professional applications that use interlaced video, this profile builds on top of the High 10 Profile, adding support for the 4:2:2 chroma subsampling format while using up to 10 bits per sample of decoded picture precision.

That's why you don't see it in consumer-aimed devices.

Quote from kszaq

High 4:2:2 Profile - as an extension of Hi10p profile - is not supported by Amlogic HW decoder (nor any known cosumer HW decoder AFAIK), it has to be software-decoded. S905 may be not powerful enough to do software decoding of 1080p 4:2:2 video.

Fallback to software decoding for High 4:2:2 profile is already covered in my development builds: projects/S*05: add more unsupported H264 encodings to HW decoding bla… · kszaq/LibreELEC.tv@448424a · GitHub

To sum up, you are not able to play 1080p High 4:2:2 videos with S905.

Which tv box with Amg soc currently supports 4: 2: 2 H264 or H265 videos either by hardware or software? S922x?

i tried a rpi4 and it doesn't work with 4: 2: 2 H264 or H265 videos

Quote from espaun206

Which tv box with Amg soc currently supports 4: 2: 2 H264 or H265 videos either by hardware or software? S922x?

i tried a rpi4 and it doesn't work with 4: 2: 2 H264 or H265 videos

Very few boxes support 4:2:2 video as it isn't a consumer format (DVD, DVB TV broadcasts, Blu-ray, UHD Blu-ray, Netflix, Prime etc. are all 4:2:0) so there is no reason to implement it in chipsets aimed at consumer devices.

4:2:2 h.264/h.265 is only used by broadcasters on contribution circuits - not final-leg distribution - so unless you are building a box for feed hunters (a small market) 4:2:2 isn't really a 'must have' feature.

None of the AMLogic chipsets that I am aware of support 4:2:2 hardware decode for this reason - so you need a box fast enough to decode it (and if it's interlaced also YADIF or W3DIF 2x deinterlace it) with CPU power.

The only ARM media player platform that I know that can currently do software decode (and deinterlace) of 1080i25 for MPEG2 and h.264 4:2:2 is the Apple TV 4K (the ARM SoC in that is a beast)

The other BIG advantage of the Apple TV 4K is that it has hardware acceleration support for 4:4:4 and 4:2:2 h.265/HEVC decode - because Apple use that codec for their Airplay/Sidecar iPad dual display function which compresses desktop video to h.265 for carriage over WiFi or Lightning/USB Type-C connection (to avoid reducing the chroma res to 4:2:0 and it all going smeary when you use your iPad as a second display) The Apple TV also has that functionality. I've played 2160p50 4:2:2 h.265/HEVC on the Apple TV in mrMC with very low CPU (but it was still not perfect because of some A/V sync issues)

If you want MPEG2 and h.264 4:2:2 with LibreElec then a decent Intel or AMD solution is probably your best bet - I used to use a Haswell i5 NUC to play 4:2:2 stuff and it coped - just - once multithreaded software decode of h.264 was implemented in ffmpeg. However the LibreElec implementation seemed to do a 4:2:2 to 4:2:0 conversion without interlaced aware chroma decode/conversion so you had saturated areas deinterlaced with p25 rather than p50 motion (a known issue in ffmpeg)