[Mp4-tech] Rate control model updating possible bugs?

[Leontaris, Athanasios]

Dear Evan,
Your proposed changes should in theory work fine. If you could provide us with feedback whether the rate control operation remains correct, this would be greatly appreciated.
Note that when the rate control code was modified in the JM 12.x versions an effort was made to keep the core functionality close to the pre-12.x versions. If you could take a look at the source code of, say, the JM 10.2, you will see the following lines:
for (i = 19; i > 0; i--) 
    {// update the history
RC_MODE_HISTORY-2 = 19
for (i = 0; i < 20; i++) 
    {
RC_MODEL_HISTORY-1 = 20
When we rewrote the rate control source code, we also fixed a large number of problems apart from reorganizing it (see JVT contribution JVT-W042), however we took care not to alter the base rate control algorithm. Indeed, it would be really helpful if we could have feedback on these parameters from the original contributors of this algorithm. Again thank you for pointing this out as it helps improve the H.264/AVC reference software.
Best regards,
Thanasis
-----Original Message-----
From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Evan Tan
Sent: Friday, May 18, 2024 9:29 PM
To: mp4-tech lists.mpegif.org
Subject: [Mp4-tech] Rate control model updating possible bugs?
Dear Experts,
In rc_quadratic.c - updateRCModel(), the update history loop:
for (i = (RC_MODEL_HISTORY-2); i > 0; i--) {// update the history ...
}
shouldn't it be:
for (i = (RC_MODEL_HISTORY-1); i > 0; i--) ?
and also in the updateRCModel():
for (i = 0; i < (RC_MODEL_HISTORY-1); i++) {
  m_rgRejected[i] = FALSE;
}
shouldn't it be:
for (i = 0; i < RC_MODEL_HISTORY; i++) ?
the same applies to updateMADModel()
Thanks,
Evan
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