And since it’s RealVideo and not Thor (and its Norwegian developer does not seem to work any more on it) all codebooks are static (total over 32k entries) and stored in compact and obfuscated form.
Transforms are present in 4×4, 8×8 and 16×16 sizes that are some poor integer approximations of DCT.Īnd now for the juiciest part: coefficients coding! Coefficients are coded with with lots of context-adaptive codebooks, for intra/inter, luma/chroma and various quantisers. Spatial (aka intra) prediction is very close to H.EVC as well. I obviously expected 1/5-pel MC for RV5 but instead they’ve stopped on 1/4-pel MC (with the bog standard 1 -5 20 20 -5 1 filter for luma and bilinear interpolation for chroma too). RV2 had 1/2-pel MC, RV3 had 1/3-pel MC, RV4 had 1/4-pel MC. The biggest disappointment is motion compensation of course. RV60 has rather simple frame header and coding units are always size 64 and they seem to comprise all three planes instead of coding planes separately. It’s the problem with many standardised codecs: you have so much flexibility in configuring coding parameters that you have to invent special objects to signal coding parameters for the following group of frames unless you want to waste 10% of bitrate on them in every slice header and then you invent profiles because not all of the features can be supported by existing hardware (for example, because they’ve not been added to the standard yet). It is oriented on multi-threading decoding and they have a lot of crap cut out and thrown away and I fully approve that. Either they thought it’s too advanced to be merely RV50 or NGV was intended to be RV50 but they’ve buried it in the same grave with MPEG-3 and such.Īnyway, it’s time for juicy technical details. It turns out that RMHD corresponds to RealVideo 11 or RV60. The actual decoder was in a separate library though with the usual interface for RealVideo decoders and obviously I could not resist looking inside. Good luck obtaining the modified source though. And since it’s China it bundles CEmpeg libraries with RMHD support built-in.
Two years ago I’ve made some predictions about upcoming RealMedia HD and little I knew that it was finished in 2015! So finally I’ve had a look at it and here are some details.įirst of all, it seems to be China-oriented since the only version with RMHD support I was able to find (even from US site) was Chinese version of RealMedia player (stream in peace…).
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