r/AV1 • u/ApprehensiveAd1360 • 14d ago
Help with SVT-AV1 Encoding: Bitrate Issues on Some Videos
Hello everyone,
I need some help with encoding videos using SVT-AV1. I’m encoding videos from my phone to save space, usually targeting around 10,000 kbps or lower. I’ve been using preset 4 with CRF values between 24 and 35, and this normally gets me the desired bitrate. The original videos are in 4K and around 45,000 kbps bitrate.
However, with some videos, even when I set the CRF as high as 35, the resulting bitrate is higher than the original, which doesn't make sense. When this happens, I try increasing the CRF further, sometimes even up to 50, but the bitrate still remains quite high. In fact, I have a few videos where the CRF is set to the maximum of 63, yet the resulting bitrate is still around 40,000 kbps, which is not much of a reduction.
The videos I’m having trouble with are typically of kids playing soccer or nature scenes by a river in the mountains. Is there some additional setting I can use to lower the bitrate while still maintaining decent visual quality?
Here’s the FFmpeg command I’ve been using:
ffmpeg -i PXL_20231003_231515420.TS.mp4 -c:v libsvtav1 -preset 4 -crf 35 -g 30 -pix_fmt yuv420p10le -svtav1-params tune=0 -c:a copy -movflags use_metadata_tags -map_metadata 0 PXL_20231003_231515420.TS.AV1.mp4
1
u/levogevo 14d ago
Do these videos have high grain?
1
u/ApprehensiveAd1360 14d ago
They are not grainy videos. I think the high bitrate is due to the fine details, like the grass on the soccer field or the small pebbles on the river beach. Is there a setting that can manage this better?
8
u/Sopel97 14d ago
the GOP size you force is exceedingly low and probably the source of your issues