Decoding 5 x UHD @ 30fps possible with kepler architecture?

I’ve been testing the NVDECODE API and was able to run some benchmarks where I decode 5 UHD videos @ 30fps with a GTX680 and render them with GL interop. I’m really, really surprised that I was able to decode 5 UHD and render them at this speed. I’ve tested the Intel hw-accell and I could barely do 2-3 UHD videos (that was on a HD4000 though, so a bit older).

Now, I’m really curious if I have a bug somewhere and my numbers are just plain wrong, or if someone else can confirm these numbers?

Decoding depends on video source. If you have only P-frames (infinite GOP) and ±static pictures the decoder can achieve such a speed.
Nvidia did some relevant benchmarks - open “NVDEC_Application_Note.pdf” from NVidia Video SDK and read section “4. NVDEC PERFORMANCE”: Kepler - 161 FPS (H264, YUV420, FullHD) - 161/4(UHD)/30(FPS) = 1.3 UHD@30fps realistic streams.

Thanks mcerveny. With static pictures do you mean IDR frames? The streams I’ve been testing with were just some general videos from Youtube or 4K sample videos I found on the web. But to make sure I just checked some of these files and they are using P and I frames only. Roughly a GOP of 60 frames.

The NVDEC_Application_Note.pdf shows indeed 161fps for 1080p. I’m curious how the streams was encoded that they used to do the benchmark. As 1HD compared to 5 x UHD is a big difference, right. I would have expected that the decoder would choke with that amount of data.

As a side note, I tested playback on a GTX670 and the GTX670 could only decode 1 UHD, with 2 the FPS dropped to 5. What could be the reason why, they have the same architecture.

No. I mean one I-frame (IDR) and infinite number of very small P-frames. Decoder is not PTS locked or V-SYNC locked and decoding ASAP.

1xUHD is expected per chip (161/4/30=1.3 UHD@30fps). The decoding scales linearly with resolution if the content has same characteristics (in fact it is limited by decoded macrobloks+luma samples per second - see
Can you disclosure identification your super fast “Kepler card” ?