Yes, its Driftwood from GH2 settings, anyone gotta problem with that!?
Yeah, judging by baseline 66 work I did on the GX1 camera there's not much one can do with any of the canons prior to the 5DmkIII - sure you can get higher bitrates and change GOP but most baseline profiles are constrained. See constrain flags in the h264 SPS set.
So the 5Dmk3 has distinct possibilities: Gonna have to sell the other canons to buy one ;-)
Level 5 mode:
I would perhaps leave the initial QPs alone - anything lower than 16 causes problems. There is also minimum QP for each P_slice type at 10 - the GH3 has something similar I believe. Subsequently, in these recording modes a scaling matrix is not being used/implemented. As a whole Scalers work best at coding the luma frequencies better - ring artefacts etc... but Canon's encoder interp. probably deems them unneccesary. Are the recordings when analysed in SPS/PPS using QP_delta offsets like =0 (no change in QP from previous prediction) or other values (e.g.-4, -6, -8, -10) that indicate a change of QP?
QpOffsetForB = 0 For B frames no QP offset variation is being employed?
Transform8x8Flag = 2 probably means adaptive 8x8/4x4 transform on residuals - ie most of the picture is coded with 8x8 and some of the luma residuals are receiving 4x4. My 'hunch' is if it were =0 all luma residual samples are receiving 4x4 block transform, or =1 are luma samples are in residual 8x8 block transform. I would leave that alone if this was confirmed as the case. A quick check with stream analysis will confirm transform being used.
EntropyCodingMode = 0
You need to establish the order of the setting e.g. does = 0 mean cavlc, 1= cabac, 3= Exp Golomb vlc - one or the other. (therefore probably 0, 1 or 2 are the available settings)
RateControlEnable = 2 - needs experimenting (first with =0, then =1) Could be some sort of adaptive rate control schemes. Could be any of the following:-
=0 - Original quadratic rate control scheme based on JVT spec
=1 - Extension of quadratic scheme for all Intra and IBsBsBs… coding.
=2 - Basic extension of quadratic scheme to better support hierarchical codingstructures
=3 - Extension of quadratic scheme with slice type separation
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Level: 4.1 modes:
IntraPicInitQP = 28
InterPicInitQP = 28
I see no reason why these cant be improved (changed to =20 as a starting point ) with tests on added bitrate to correct rate control.
I really need the developer to find a patch in their firmware/ROM/RAM loadables for coded picture buffer (surely there's something in there?) as just adding bitrate requires more buffer bitrate (whats the ceiling?) In the GH2 ptools we have it as a 'bottom' setting, 'Top' setting being bitrate. Also anything regarding Frame buffers (and sizes), and frame size in bits?
Can someone load up a 5dmk3 PPS produced from elecard or any other h264 stream analysis software?
And can someone please email me a few small sized original .mov recordings from the mk3?
more to come...
