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--- ubuntu:video:ffmpeg:hardware_acceleration_using_gpu:amd_gpu:benchmark [2023/06/13 10:06] – peter
+++ ubuntu:video:ffmpeg:hardware_acceleration_using_gpu:amd_gpu:benchmark [2023/06/13 10:23] (current) – removed peter
@@ Line 1: / Line 1: @@
-====== Ubuntu - Video - ffmpeg - Hardware Acceleration using GPU - AMD GPU - Benchmark ======
-===== Null muxer =====
-A simple way to benchmark decoding is to use the null muxer:
-<code bash>
-ffmpeg -i input -f null -
-</code>
-<WRAP info>
-**NOTE:**  The following parts of the command forces a null file: <code bash>
--f null -
-</code>
-</WRAP>
-----
-===== Timing decoding =====
-Linux and macOS users can add the time command:
-<code bash>
-time ffmpeg -i input -f null -
-</code>
-returns:
-<code bash>
-[...]
-real	0m3.115s
-user	0m0.223s
-sys	0m0.244s
-</code>
-<WRAP info>
-**NOTE:**  See **man time** for more info.
-</WRAP>
-----
-===== Benchmark option =====
-The **-benchmark** option can be added to output CPU time and maximum memory consumption:
-<code bash>
-time ffmpeg -i input -benchmark -f null -
-</code>
-returns:
-<code bash>
-[...]
-bench: utime=0.154s stime=0.196s rtime=3.000s
-bench: maxrss=365256kB
-</code>
-----
-===== Choosing streams =====
-If you want to just decode a particular stream then use the map option:
-<code bash>
-ffmpeg -i input -map 0:a:0 -f null -
-</code>
-<WRAP info>
-**NOTE:**  Another approach to ignore streams is to use:
-  * **-an** to ignore audio streams.
-  * **-vn** to ignore video streams.
-</WRAP>
-----
-===== Threads =====
-You can decode with one thread if you want to:
-<code bash>
-ffmpeg -threads 1 -i input -f null -
-</code>
-<WRAP info>
-**NOTE:**  Not all decoders have threading capabilities and some have several.
-You can check decoder details such as <code bash>ffmpeg -h decoder=h264</code>
-</WRAP>
-----
-===== Choosing a decoder =====
-There can be several decoders available for a format.
-You can name the decoder if you do not want to rely on the default:
-<code bash>
-ffmpeg -c:v vp8 -i input -f null -
-ffmpeg -c:v libvpx -i input -f null -
-</code>
-----
-===== Example =====
-<code bash>
-ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -hwaccel_output_format vaapi -i input.mp4 -c:v hevc_vaapi -q:v 28 -f null - -benchmark
-</code>
-returns:
-<code bash>
-...
-bench: utime=0.156s stime=0.195s rtime=3.003s
-bench: maxrss=358944kB
-</code>
-<WRAP info>
-**NOTE:**  **maxrss** indicates the maximum RAM used during the ffmpeg execution.
-  * **utime**: user time.
-    * utime is the sum of processing time across all threads. Since they may operate in parallel, utime can exceed rtime.
-  * **stime**: system time.
-  * **rtime**: real time.
-</WRAP>