I am experimenting with hevc_nvenc and I am having trouble getting a high quality image with VBR mode. I tried giving it a super high bitrate of 100Mbps but this only encodes 29Mbps, which makes me think I am missing some important setting. How can I make it use more bits, and are there any other parameters I should try for better quality? I’m using Tesla T4. I tried B frame refs instead of weighted prediction but that didn’t make any difference and I believe you can’t use both at the same time. I’ve tried several different combinations of nvenc parameters, but I am not sure if I need to also adjust any ffmpeg options too. Here’s an example command. I can post before/after images if it helps. The main problem is blocky artifacts in the darker areas.
$ ffmpeg -y -i ArriHD_short.mov -pix_fmt yuv444p16le -an -c:v hevc_nvenc -preset p7 -tune hq -profile:v main10 -rc vbr -rc-lookahead 24 -weighted_pred 1 -spatial-aq 1 -b:v 100M aq-weigh.mkv ffmpeg version N-100390-ge0e9c94c2b Copyright (c) 2000-2020 the FFmpeg developers built with gcc 7 (GCC) configuration: --enable-gpl --enable-nonfree --enable-nvenc --enable-libx264 --enable-libx265 --enable-libfdk_aac --enable-libopus --enable-libnpp --enable-cuda-nvcc --extra-cflags=-I/usr/local/cuda-10.2/targets/x86_64-linux/include --extra-ldflags=-L/usr/local/cuda-10.2/targets/x86_64-linux/lib libavutil 56. 62.100 / 56. 62.100 libavcodec 58.115.102 / 58.115.102 libavformat 58. 65.100 / 58. 65.100 libavdevice 58. 11.103 / 58. 11.103 libavfilter 7. 92.100 / 7. 92.100 libswscale 5. 8.100 / 5. 8.100 libswresample 3. 8.100 / 3. 8.100 libpostproc 55. 8.100 / 55. 8.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'ArriHD_short.mov': Metadata: major_brand : qt minor_version : 537199360 compatible_brands: qt creation_time : 2020-12-10T22:41:31.000000Z Duration: 00:00:20.25, start: 0.000000, bitrate: 175506 kb/s Stream #0:0(eng): Video: prores (HQ) (apch / 0x68637061), yuv422p10le(tv, bt709, progressive), 1920x1080, 173968 kb/s, SAR 1:1 DAR 16:9, 24 fps, 24 tbr, 24 tbn, 24 tbc (default) Metadata: creation_time : 2020-12-10T22:41:31.000000Z handler_name : Apple Video Media Handler vendor_id : appl encoder : Apple ProRes 422 HQ timecode : 00:00:12:21 Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default) Metadata: creation_time : 2020-12-10T22:41:31.000000Z handler_name : Apple Sound Media Handler vendor_id : [0][0][0][0] Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default) Metadata: creation_time : 2020-12-10T22:41:31.000000Z handler_name : Time Code Media Handler reel_name : 01_NAB2017_ARRI_Camera_Showreel_Part01_UHD_WL_HDR10_24fps_stereo24bit timecode : 00:00:12:21 Stream mapping: Stream #0:0 -> #0:0 (prores (native) -> hevc (hevc_nvenc)) Press [q] to stop, [?] for help Output #0, matroska, to 'aq-weigh.mkv': Metadata: major_brand : qt minor_version : 537199360 compatible_brands: qt encoder : Lavf58.65.100 Stream #0:0(eng): Video: hevc (Rext), yuv444p16le(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 100000 kb/s, 24 fps, 1k tbn (default) Metadata: creation_time : 2020-12-10T22:41:31.000000Z handler_name : Apple Video Media Handler vendor_id : appl timecode : 00:00:12:21 encoder : Lavc58.115.102 hevc_nvenc Side data: cpb: bitrate max/min/avg: 0/0/100000000 buffer size: 200000000 vbv_delay: N/A frame= 486 fps= 88 q=14.0 Lsize= 72130kB time=00:00:20.20 bitrate=29238.8kbits/s speed=3.64x video:72125kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.007138% _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".