Where can I find the intra-only config file for VVEnc equivalent to VTM's intra-only configuration?

[eimran-eimon]

In this repository, only random access configuration files with different preset are provided. But there is no config file present for intra-only configuration. Can anyone provide me with the intra-only config file for the VVenc?

Thanks.

[adamjw24]

There is no intra-only configuration files provided for intra-only encoding. You can use the RA configuration files and just add the following options to your call --IntraPeriod=1 --GOPSize=1 --MaxParallelFrames=1, e.g. in a following call:

vvencFFapp -i input.yuv -c sequence.cfg -c rancomaccess_medium.cfg --IntraPeriod=1 --GOPSize=1 --MaxParallelFrames=1

Motion compensation and appropriate tools will not be used, so theres nothing to worry about.

We do not calculate a intra-only pareto set, so the presets will not be optimal, but should provide a good quality/runtime scaling.

Since it is not officially supported or optimal, it is not possible to do this using the simple app.

See the following paper some more info:

• A. Wieckowski, C. Stoffers, B. Bross, D. Marpe, "VVenC, an open optimized VVC encoder, in versatile application scenarios," Proc. SPIE 11842, Applications of Digital Image Processing XLIV, 118420H (1 August 2021), doi: 10.1117/12.2595360.

[eimran-eimon]

Thanks for your prompt response.

So, we only have to pass these three parameters --IntraPeriod=1 --GOPSize=1 --MaxParallelFrames=1 along with the main command to make the config file equivalent to the VTM's intra-only config, or do we have to change any other config parameters? What about the "DecodingRefreshType" parameter? Should we keep it the same?

Suppose we choose to use the "randomaccess-slower.cfg" by changing those parameters as mentioned above. Could we expect that the bit-per-pixel (bpp) of the encoded file and PSNR will be the same as if we have to use the VTM encoder with the intra-only config? What about the speed-up of the VVEnc in that case? Will it be always faster than the VTM?

[adamjw24]

The DecodingRefreshType parameter is free for you to choose. If you keep it at default you'll get an IDR picture followed by CRA pictures, just as VTM does. Setting it 2, will give you an IDR picture followed by IDR_W_RASL (but of course without the actual RASL pictures). There's currently no option to produce IDR pictures only.

About the bits-per-pixel and PSNR, I cannot really tell. Please have a look at the graph below, which shows the performance of VVenC 1.0 and VTM in the all-intra config. VVenC is always faster than VTM, but not by such a high margin as with random access. The BDR is a combined metric describing both the rate and the quality (bpp and PSNR), so I cannot tell if both will be the same. But combined as an expected rate saving vs HM, VVenC slower has very similar performance to VTM.