Add OBS/ffmpeg instructions with AMD vaapi

pc_fedora.md

@@ -102,7 +102,8 @@ And timers to run the btrbk services on a regular schedule.
 Description=Run btrbk_snapshots every hour
 
 [Timer]
-OnCalendar=hourly
+OnCalendar=hourlyalways want to give it a device name; the implicit selection may be right in some cases but it's better not to rely on it.
+
 AccuracySec=10min
 Persistent=true
 Unit=btrbk_snapshots.service
@@ -334,10 +335,14 @@ flatpak update
 
 ## Steam
 
+### Install ProtonUp-Qt
+
 ```bash
 flatpak install flathub net.davidotek.pupgui2
 ```
 
+### Install Steam
+
 ```bash
 sudo dnf install https://mirrors.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm
 sudo dnf install steam
@@ -348,9 +353,24 @@ cd ~/.local/share/Steam/
 ./steam.sh --reset
 ```
 
+### Enable OBS Game Capture
+
+<https://github.com/nowrep/obs-vkcapture>
+
+```bash
+sudo dnf install cmake gcc gcc-c++ obs-studio-devel mesa-libGL-devel vulkan-loader-devel
+
+git clone ssh://git@gitea.reeseapps.com:2222/mirrors/obs-vkcapture.git
+mkdir build && cd build
+cmake -DCMAKE_INSTALL_PREFIX=/usr ..
+make && make install
+```
+
+Add `env OBS_VKCAPTURE=1 %command%` to your launch options for the game you want to capture.
+
 ## OBS
 
-https://www.reddit.com/r/linux_gaming/comments/w4i3qf/easy_way_to_get_good_4k_60fps_obs_encoding/
+<https://www.reddit.com/r/linux_gaming/comments/w4i3qf/easy_way_to_get_good_4k_60fps_obs_encoding>
 
 ```bash
 sudo flatpak install \
@@ -360,10 +380,44 @@ sudo flatpak install \
     com.obsproject.Studio.Plugin.OBSVkCapture
 ```
 
+Create a new scene and add "Game Capture" to it. When you start a game with the above
+launch option (`env OBS_VKCAPTURE=1 %command%`) OBS will automatically pick it up.
+
 Use advanced settings to select the GStreamer encoder and the VA-API encoder type.
 
 ![obs_hardware_encoding_settings](obs_hardware_encoding.png)
 
+## FFMPEG with hardware encoding/decoding
+
+First you'll need mesa-va-drivers-freeworld which provides x264 and hevc support for
+vaapi decoding. First you'll need to install [https://rpmfusion.org/Configuration](rpm fusion).
+Then the freeworld drivers need to be swapped with mesa-va-drivers:
+
+```bash
+sudo dnf swap mesa-va-drivers mesa-va-drivers-freeworld
+```
+
+To check what hardware decoding is supported by your system you'll need vainfo:
+
+```bash
+sudo dnf install libva-utils
+```
+
+Running `vainfo` will show all available profiles. You should see H264, HEVC, AV1, and VP9.
+
+Then with ffmpeg you can run
+
+```bash
+ffmpeg \
+-hwaccel vaapi \
+-vaapi_device /dev/dri/renderD128 \
+-hwaccel_output_format vaapi \
+-i input.mkv \
+-c:v hevc_vaapi \
+-b:v 0 \
+test.mp4
+```
+
 ## Power Button Behavior
 
 The power button is controlled from 2 locations: