I was testing the efficiency changes going from SVT-AV1 v1.1.0 to SVT-AV1 v1.2.1 on Windows, and found that for some reason the 10-bit encoding took a major hit in performance. I did a `git bisect` to figure out which commit this occurred in, and found that it regressed in commit https://gitlab.com/AOMediaCodec/SVT-AV1/-/commit/1d842ee644de1841bb8cfc167e280ab9082cf4c7 as part of PR https://gitlab.com/AOMediaCodec/SVT-AV1/-/merge_requests/1947. From my testing, I found that 8-bit encoding stayed the same performance, but 10-bit encoding dropped by as much as **_one-third_** of what it once was before the commit depending on the preset used. I tested the presets from 6 to 12 on an AMD Ryzen 9 5950X, using both 8-bit and 10-bit encoding for an 8-bit source; I lack a 10-bit source to test with. I checked with both `tune=0` and `tune=1` and found similar performance regressions, so I'm only showing the results for `tune=0` here. I didn't test any preset below 6 for the sake of time, so I'm not sure if this behavior is reflected in slower presets. I assume it would be just as much of hit. I compiled targeting the _Release_ build using Visual Studio 2022, though I was also able to reproduce this behavior using `libsvtav1` in FFmpeg v5.1.1 via the [gyan.dev](https://www.gyan.dev/ffmpeg/builds/) Windows builds. I also tested this in Linux using WSL Ubuntu 20.04, and I didn't see the same performance hit between bit depths. _So to be clear, this seems to be an issue exclusive to Windows._ The source doesn't seem to matter, but if you want to specifically use mine, [you can download it here](https://drive.google.com/file/d/1Z485-lwmPdY8tn7oPGFG2nhHpYtapnLg/view?usp=sharing). **8-bit Command**: `ffmpeg -i G:\lossless\tf2_lossless.avi -nostdin -f yuv4mpegpipe - | .\SvtAv1EncApp.exe -i stdin --input-depth 8 --preset 7 --crf 14 --tune 0` **8-Bit Example Output:** ``` Svt[info]: Number of logical cores available: 32 Svt[info]: Number of PPCS 88 Svt[info]: [asm level on system : up to avx2] Svt[info]: [asm level selected : up to avx2] Svt[info]: ------------------------------------------- Svt[info]: SVT [config]: main profile tier (auto) level (auto) Svt[info]: SVT [config]: width / height / fps numerator / fps denominator : 1920 / 1080 / 60 / 1 Svt[info]: SVT [config]: bit-depth / color format / compressed 10-bit format : 8 / YUV420 / 0 Svt[info]: SVT [config]: preset / tune / pred struct : 7 / VQ / random access Svt[info]: SVT [config]: gop size / mini-gop size / key-frame type : 321 / 16 / key frame Svt[info]: SVT [config]: BRC mode / rate factor : CRF / 14 Svt[info]: ------------------------------------------- SUMMARY --------------------------------- Channel 1 -------------------------------- Total Frames Frame Rate Byte Count Bitrate 1801 60.00 fps 196025484 52244.44 kbps Channel 1 Average Speed: 30.016 fps Total Encoding Time: 60001 ms Total Execution Time: 61001 ms Average Latency: 3153 ms Max Latency: 5000 ms ``` **10-bit Command**: `ffmpeg -i G:\lossless\tf2_lossless.avi -nostdin -f yuv4mpegpipe -pix_fmt yuv420p10le -strict -1 - | .\SvtAv1EncApp.exe -i stdin --input-depth 10 --preset 7 --crf 14 --tune 0` **10-Bit Example Output:** ``` Svt[info]: Number of logical cores available: 32 Svt[info]: Number of PPCS 88 Svt[info]: [asm level on system : up to avx2] Svt[info]: [asm level selected : up to avx2] Svt[info]: ------------------------------------------- Svt[info]: SVT [config]: main profile tier (auto) level (auto) Svt[info]: SVT [config]: width / height / fps numerator / fps denominator : 1920 / 1080 / 60 / 1 Svt[info]: SVT [config]: bit-depth / color format / compressed 10-bit format : 10 / YUV420 / 0 Svt[info]: SVT [config]: preset / tune / pred struct : 7 / VQ / random access Svt[info]: SVT [config]: gop size / mini-gop size / key-frame type : 321 / 16 / key frame Svt[info]: SVT [config]: BRC mode / rate factor : CRF / 14 Svt[info]: ------------------------------------------- SUMMARY --------------------------------- Channel 1 -------------------------------- Total Frames Frame Rate Byte Count Bitrate 1801 60.00 fps 205898009 54875.65 kbps Channel 1 Average Speed: 10.118 fps Total Encoding Time: 178000 ms Total Execution Time: 178001 ms Average Latency: 9006 ms Max Latency: 14000 ms ``` **Commit https://gitlab.com/AOMediaCodec/SVT-AV1/-/commit/0ba91fc4bb19ac8ad02b668cf5da5a82b7caa21a (the last known good commit) Results:** | Preset | Bit Depth | FPS | | ------ | ------ | ------ | | 6 | 8 | 15.526 | | 6 | 10 | 14.408 | | 7 | 8 | 30.525 | | 7 | 10 | 26.88 | | 8 | 8 | 66.703 | | 8 | 10 | 58.094 | | 9 | 8 | 100.052 | | 9 | 10 | 78.304 | | 10 | 8 | 128.642 | | 10 | 10 | 100.055 | | 11 | 8 | 138.536 | | 11 | 10 | 112.561 | | 12 | 8 | 180.088 | | 12 | 10 | 138.528 | **Commit https://gitlab.com/AOMediaCodec/SVT-AV1/-/commit/1d842ee644de1841bb8cfc167e280ab9082cf4c7 (the first known bad commit) Results:** | Preset | Bit Depth | FPS | | ------ | ------ | ------ | | 6 | 8 | 15.263 | | 6 | 10 | 5.772 | | 7 | 8 | 31.051 | | 7 | 10 | 10.175 | | 8 | 8 | 66.703 | | 8 | 10 | 27.707 | | 9 | 8 | 100.053 | | 9 | 10 | 26.485 | | 10 | 8 | 128.641 | | 10 | 10 | 33.981 | | 11 | 8 | 138.535 | | 11 | 10 | 60.033 | | 12 | 8 | 180.087 | | 12 | 10 | 94.789 | Here's a bar graph that shows the relative performance change for each preset and each 10-bit, in other words _new FPS / old FPS_.