As far as I remember:
a. rc-lookahead (mbtree/vbv-lookahead) is only used in x264 when mbtree is enabled.
b. with '--no-mbtree', Hybrid will not add '--rc-lookahead' to the command line. So Hybrid should never set '--rc-lookahead 0'.
c. rc-lookahead is restricted by min(--keyint,250) or min(--keyint/2, 250). (not sure atm.)
If you are sure one or all of these statements are false, please share the links to where this is in the x264 source code, since I'm pretty sure I checked this when I implemented it in Hybrid.
I think, what happens is, that you disabled mbtree. x264 doesn't use rc-lookahead and thus sets it to 0 in the SEI data (this is what MediaInfo looks at to report the 'Encoding setting').
I'm pretty sure this i not a bug in Hybrid, but a correct mirror of how x264 behaves.
Setting rc-lookahead = 0 in x264 does not entirely disable rate control. Instead, it disables the lookahead process for rate control decisions, meaning the encoder will not analyze future frames to optimize bitrate allocation. However, other rate control mechanisms (e.g., CRF, ABR, or CBR) remain active unless explicitly disabled or overridden by other parameters like constant quantizer mode (--qp) or specific configurations (like qcomp = 0 which basically is --cq).
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upper limit 250: https://github.com/PlatformLab/x264/blob...ase.h#L128
for the rest, see: https://code.videolan.org/videolan/x264/...eads#L1108
this was also discussed over at doom9s a few years ago.
Cu Selur
a. rc-lookahead (mbtree/vbv-lookahead) is only used in x264 when mbtree is enabled.
b. with '--no-mbtree', Hybrid will not add '--rc-lookahead' to the command line. So Hybrid should never set '--rc-lookahead 0'.
c. rc-lookahead is restricted by min(--keyint,250) or min(--keyint/2, 250). (not sure atm.)
If you are sure one or all of these statements are false, please share the links to where this is in the x264 source code, since I'm pretty sure I checked this when I implemented it in Hybrid.
I think, what happens is, that you disabled mbtree. x264 doesn't use rc-lookahead and thus sets it to 0 in the SEI data (this is what MediaInfo looks at to report the 'Encoding setting').
I'm pretty sure this i not a bug in Hybrid, but a correct mirror of how x264 behaves.
Setting rc-lookahead = 0 in x264 does not entirely disable rate control. Instead, it disables the lookahead process for rate control decisions, meaning the encoder will not analyze future frames to optimize bitrate allocation. However, other rate control mechanisms (e.g., CRF, ABR, or CBR) remain active unless explicitly disabled or overridden by other parameters like constant quantizer mode (--qp) or specific configurations (like qcomp = 0 which basically is --cq).
----
upper limit 250: https://github.com/PlatformLab/x264/blob...ase.h#L128
for the rest, see: https://code.videolan.org/videolan/x264/...eads#L1108
this was also discussed over at doom9s a few years ago.
Cu Selur
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Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.
Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.