Doom9's Forum - View Single Post

LoRd_MuldeR · 19th January 2012, 13:22

Encoding with x264 in constant quantizers (CQ) mode usually is a very bad idea, though possible (if you insist).

Anyway, x264 still gives higher quantizers to B- and P-Frames, as controlled by the "I- and P-Frame Quantizer Ratio" and the "P- and B-Frame Quantizer Ratio".

This is done for a good reason and you shouldn't touch it. Again, if you insist, you can set these ratios to 1.0 and force the same quantizer on all frames.

In CRF mode x264 will adjust the quantizer to the content of the video. It will also use Adaptive Quantization in CRF mode, while this is not possible in CQ mode.

To make a long story short: Use CRF mode, unless you have a very good reason not to do so.

(BTW: The "Min Quantizer" and ""Max Quantizer" options still apply in CRF mode. They just restrict x264's choice of the quantizer. Leave these at default!)

19th January 2012, 13:22	#5 \| Link
LoRd_MuldeR Software Developer Join Date: Jun 2005 Location: Last House on Slunk Street Posts: 13,248	Encoding with x264 in constant quantizers (CQ) mode usually is a very bad idea, though possible (if you insist). Anyway, x264 still gives higher quantizers to B- and P-Frames, as controlled by the "I- and P-Frame Quantizer Ratio" and the "P- and B-Frame Quantizer Ratio". This is done for a good reason and you shouldn't touch it. Again, if you insist, you can set these ratios to 1.0 and force the same quantizer on all frames. In CRF mode x264 will adjust the quantizer to the content of the video. It will also use Adaptive Quantization in CRF mode, while this is not possible in CQ mode. To make a long story short: Use CRF mode, unless you have a very good reason not to do so. (BTW: The "Min Quantizer" and ""Max Quantizer" options still apply in CRF mode. They just restrict x264's choice of the quantizer. Leave these at default!) __________________ Go to https://standforukraine.com/ to find legitimate Ukrainian Charities 🇺🇦✊ Last edited by LoRd_MuldeR; 19th January 2012 at 15:28.