problem occurs in slice quant estimation and slice encoding.
if slice quant >= MAX_STORED_Q we dont use pre-calculated quant matrices
but generate new:
qmat = ctx->custom_q;
qmat_chroma = ctx->custom_q;
for (i = 0; i < 64; i++) {
qmat[i] = ctx->quant_mat[i] * quant;
qmat_chroma[i] = ctx->quant_chroma_mat[i] * quant;
}
as you see both qmat and qmat_chroma both point to same ctx -> custom_q
as result they will contain chroma qunatizers as
qmat_chroma[i] = ctx->quant_chroma_mat[i] * quant;
last in loop, after all we pass qmat/qmat_chroma to function where we
estimate encoded slice size or encode slice:
estimate_slice_plane / encode_slice_plane
I will make new patch with detailed description
пт, 28 дек. 2018 г. в 18:43, Derek Buitenhuis <[email protected]>:
> On 27/12/2018 19:28, Alex Mogurenko wrote:
> > ---
> > libavcodec/proresenc_kostya.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
>
> Can you give a little more detail about what's changed and why,
> in the commit message?
>
> It looks like custom_chroma_q is zero initialized and never set to
> anything?
>
> - Derek
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