Video Encode API: BFrames not supported on RX 4xx?

[Xaymar]

10:41:06.215: [AMF Encoder]  Type | Acc.Type | Max Bitrate | Stream # | Max Profile | Max Level | BFrames | Ref. Frames | Layer # | FSM | Instance #   
10:41:06.215: [AMF Encoder]   AVC | Hardware |   100000000 |       16 |         100 |        52 |      No |    1 -   16 |       1 |  No |          1  
10:41:06.215: [AMF Encoder]   SVC | Hardware |   100000000 |       16 |         100 |        51 |      No |    1 -   16 |       3 |  No |          1 

I get this result when querying the AMF Encoder for capabilities. The RX 480 has a newer VCE (sub-)generation, shouldn't it support BFrames like the R9 380/R9 285?
This is the output when I select the R9 285 (using the older SDK).

10:41:06.215: [AMF Encoder]  Type | Acc.Type | Max Bitrate | Stream # | Max Profile | Max Level | BFrames | Ref. Frames | Layer # | FSM | Instance # 
10:41:06.215: [AMF Encoder]   AVC | Hardware |  1000000000 |       16 |         100 |        51 |     Yes |    1 -   16 |       1 |  No |          1 
10:41:06.215: [AMF Encoder]   SVC | Hardware |  1000000000 |       16 |         100 |        42 |     Yes |    1 -   16 |       3 |  No |          1 

[MikhailAMD]

Yes, R9 480 does not support B-frames. You can try new SDK on both HW for consistency.

[kytos22]

I think you meant RX480, if so how is this possible?

[MikhailAMD]

Yes, HW change.

[Xaymar]

Does that mean that Vega and Polaris will not support B-Frame encoding, lowering recording quality? That seems like a strange upgrade from VCE 3.0, are you sure it isn't temporarily disabled until the driver side libraries are ready?

[Roph]

Not totally related, but Polaris definitely supports B-Frames when encoding H.265. Encoding some now.

[Xaymar]

@Roph Using the AMF SDK or Media Foundation implementation?

[Roph]

Using a very early development transcoder. I believe the developer used the new SDK.

[kytos22]

AMD_Robert just said it may be a mistake: https://www.reddit.com/r/Amd/comments/4y10gr/today_we_released_a_new_version_of_the_amd_media/d6qb71o

[MikhailAMD]

AMD does not support B-frames for HEVC and H264 on this chip yet.

[Roph]

Are you sure about that? Using an early test build transcoder I'm able to specify B-frames from 0-3 using HEVC on VCE:

You can find test transcodes/discussion here: http://forum.videohelp.com/threads/380081-AMD-Polaris-(Radeon-RX-4xx)-H265-Encoding-Samples

I'm not able to check for the presence of actual B-frames in the resulting HEVC video; MediaInfo is the most verbose tool I know of and that doesn't specify.

[Xaymar]

@Roph: If I read your thread right, you have access to a private repository for the SDK? Does that mean that whatever is currently forcing BFrame support to off is version-specific for the SDK?

I've seen many log files for the RX 4xx series now and the capability reporting always shows BFrames as "Not Supported".

[Roph]

Not to the SDK, a developer of VCE-enabled video transcoding software put together an untested new build for me using the new SDK with H265 support. He doesn't have a polaris GPU to test on yet.

It definitely works and produces good (for a GPU) quality HEVC, I can't confirm if it's actually using B-Frames though.

[Xaymar]

But... the SDK doesn't have H265 support yet. Unless he is using the Media Foundation encoder, then it would make sense. (Still impressive speeds for media foundation)

[nwgat]

StreamEye can show you if it encodes b-frames or not but it seems not to work on roph's files for some reason even after remux to mkv