HW decoding and encoding explanation

[b4inception]

Can someone help out a transcoding newbie. I understand transcoding, but what I don’t understand is the following from the Plex manual.

When hardware acceleration is being used, you should see (hw) next to the Video format as shown above.

• The status text will show Video Transcoding [FORMAT] (hw) to [FORMAT] (hw) .
• The first (hw) indicates that hardware-accelerated video decoding is being used. Only certain video formats are supported for this.
• The second (hw) indicates that hardware-accelerated video encoding is being used.
• Depending on the video file and the server hardware, hardware acceleration can be used for decoding, encoding, or both.

The part that has me stumped is decoding and encoding the it appears that you could, in theory have a file that supports HW “decoding” BUT NOT “encoding”. I assumed that if the GPU supported either, it would support both.

So, looking for a bit of detail around the split that a file could be decoded, but not encoded, or I guess vice versa also.

Thanks for any support.

[0xDECAFBAD]

I’m interested in this also. I’m having buffering issues transcoding 4K HEVC on my Quadro P600. It supports HEVC decoding and encoding but it appears Plex is decoding with CPU and encoding with GPU.

[Elido]

Same here on a P2000.

[0xDECAFBAD]

I was told that, at least with Nvidia, there is no API to call the decoder to decode video files. I guess the decoder is only used for playback. So that’s why with hardware acceleration with Nvidia you only get (hw) with encoding. The CPU will decode and the graphics card will encode.

[Elido]

ma hart ma soul… so i’ll have to swap my 4790k for a new one? Was really hoping the P2000 could solve my transcoding issues. welp

[0xDECAFBAD]

Yeah I’m returning my P600 and probably going to end up building a new Plex server with an 8th gen core and just use Quick Sync since video card hardware acceleration seems like it doesn’t help much with Plex.