On 2016-06-01 07:32, Per Jessen wrote:
Per Jessen wrote:
Carlos E. R. wrote:
The graphics card is not used at all when converting videos to another format. Only when displaying that video.
A graphics card's GPUs might well be used during encoding/decoding/conversion. For instance, ffmpeg is able to use vaapi.
Paul, your systems are virtual identical. To test if it is an issue with the graphics card, it might be worth swapping the graphics cards. Also try "vainfo" to see if video hardware acceleration is in use/available.
Uh, with Nvidia cards, it's called VDPAU instead of VAAPI, I don't know if vainfo is aware or if there is a dedicated utility for vdpau.
I don't even have vainfo installed. :-?
vainfo comes with "vaapi-tools" which is really for Intel Graphics only. I'm sure there must be something similar for Nvidia.
I have no idea about that. There is a "vdpauinfo" here. It prints a page of information, but nothing about ffmpeg using it or not. :-? "man ffmpeg" has nothing about nvidia. There is a mention about vdpau, though: -hwaccel[:stream_specifier] hwaccel (input,per-stream) Use hardware acceleration to decode the matching stream(s). The allowed values of hwaccel are: none Do not use any hardware acceleration (the default). auto Automatically select the hardware acceleration method. vda Use Apple VDA hardware acceleration. vdpau Use VDPAU (Video Decode and Presentation API for Unix) hardware acceleration. dxva2 Use DXVA2 (DirectX Video Acceleration) hardware acceleration. qsv Use the Intel QuickSync Video acceleration for video transcoding. Unlike most other values, this option does not enable accelerated decoding (that is used automatically whenever a qsv decoder is selected), but accelerated transcoding, without copying the frames into the system memory. For it to work, both the decoder and the encoder must support QSV acceleration and no filters must be used. This option has no effect if the selected hwaccel is not available or not supported by the chosen decoder. Note that most acceleration methods are intended for playback and will not be faster than software decoding on modern CPUs. Additionally, ffmpeg will usually need to copy the decoded frames from the GPU memory into the system memory, resulting in further performance loss. This option is thus mainly useful for testing. Note that it is not enabled by default, and only used for playback, and that it says: "will not be faster than software decoding on modern CPUs" -hwaccel_device[:stream_specifier] hwaccel_device (input,per-stream) Select a device to use for hardware acceleration. ... -hwaccels List all hardware acceleration methods supported in this build of ffmpeg. The speed of ffmpeg varies a lot depending on codec selected and options. Some codecs parallelize wonderfully. Others very badly, and for those it is better to convert several media streams at the same time, one per cpu core. If the CPU is fast enough, it is the hard disk which becomes a limitation. -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)