Hi, first timer here. If I've missed any info below that may be required, please tell me.
I have two PCs I use for transcoding as follows, the Intel one being at least twice as fast at trancoding to X265 as the AMD one despite the Intel one having 2 cores (4 with hyperthreading) at 2.8GHz compared to the AMD with 6 actual cores at 3.5GHz Intel box: FreeBSD testbox.asgard.uk 10.3-RELEASE-p20 CPU: Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz (2675.02-MHz K8-class CPU) FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs real memory = 4294967296 (4096 MB) avail memory = 4098699264 (3908 MB) nvidia0: <GeForce 9500 GT> on vgapci0 ffmpeg-3.3.4,1 AMD box FreeBSD amd.asgard.uk 10.3-RELEASE-p20 CPU: AMD Phenom(tm) II X6 1100T Processor (3311.05-MHz K8-class CPU) FreeBSD/SMP: Multiprocessor System Detected: 6 CPUs real memory = 8589934592 (8192 MB) avail memory = 8249188352 (7867 MB) nvidia0: <GeForce 8400GS> on vgapci0 ffmpeg-3.3.4,1 Note that ffmpeg is built from source using the latest version in the FreeBSD ports collectionon each PC so any default local compiler or cpu optimisation which may occur based on the local hardware and CPU type ought to occur. The most obvious difference when running ffmpeg are the following lines On Intel box x265 [info]: HEVC encoder version 2.3 x265 [info]: build info [Unk-OS][clang 3.4.1][64 bit] 8bit x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 On AMD box x265 [info]: HEVC encoder version 2.3 x265 [info]: build info [Unk-OS][clang 3.4.1][64 bit] 8bit x265 [info]: using cpu capabilities: MMX2 SSE2Fast LZCNT Specifically the CPU capabilities are quite different so I suspect are the most likely reason for the difference. Are AMD CPUs not as well supported for optimised X265 encoding or is my AMD Phenom II X6 1100T simply too old by modern standards? Note that I have tried swapping the video cards between the two boxes to no effect. The general command line I'm using, with variations on the preset and CRF values depending on the source, is: ffmpeg -i input.ts -c:v libx265 -preset medium -crf 26 -c:a copy ouput.mkv sometimes with a -vf scale, sometimes transcoding the audio, but the above is probably the most common command I use. Are there any AMD specific options I should be using? I'm considering building a new PC so would appreciate any suggestions on what to look for and what to avoid. Is it primarily CPU "grunt" (+ extensions) or should I be looking at GPU too? Bearing in mind also that I run FreeBSD so CUDA is not an option (if it even is an option on any OS) _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
