Codec selection (#892)

* Query for installed codecs

* Start modeling out codecs

* Can now specify a codec and get the correct settings returned from the model

* Return codecs in admin/serverconfig

* Start handling transcoding errors and return messages to user

* filter available codecs against a whitelist

* Fix merge

* Codecs are working

* Switching between codecs work

* Add apis for setting a custom video codec

* Cleanup the logging of transcoder errors

* Add v4l codec

* Add fetching v4l

* Add support for per-codec presets

* Use updated nvenc encoding parameters

* Update log message

* Some more codec WIP

* Turn off v4l. It is a mess.

* Try to make the lowest latency level a bit more playable

* Use a human redable display name in console messages

* Turn on transcoder persistent connections

* Add more codec-related user-facing error messages

* Give the initial offline state transcoder an id

* Force a minimum segment count of 3

* Disable qsv for now. set x264 specific params in VariantFlags

* Close body in case

* Ignore vbv underflow message, it is not actionable

* Determine a dynamic gop value based on the length of segments

* Add codec-specific tests

* Cleanup

* Ignore goconst lint warnings in codec file

* Troubleshoot omx

* Add more codec tests

* Remove no longer accurate comment

* Bundle admin from codec branch

* Revert back to old setting

* Cleanup list of codecs a bit

* Remove old references to the encoder preset

* Commit updated API documentation

* Update admin bundle

* Commit updated API documentation

* Add codec setting to api spec

* Commit updated API documentation

Co-authored-by: Owncast <owncast@owncast.online>

openapi.yaml

@@ -182,9 +182,9 @@ components:
         framerate:
           type: integer
           description: The target frames per second of the video.
-        encoderPreset:
-          type: string
-          description: "The [H.264 preset value](https://trac.ffmpeg.org/wiki/Encode/H.264) selected for this HLS variant."
+        cpuUsageLevel:
+          type: integer
+          description: "The amount of hardware utilization selected for this HLS variant."
     
     TimestampedValue:
       type: object
@@ -984,13 +984,35 @@ paths:
                 - framerate: 30
                   videoPassthrough: false
                   videoBitrate: 1800
-                  encoderPreset: veryfast
+                  cpuUsageLevel: 2
                   audioPassthrough: true
                 - framerate: 24
                   videoPassthrough: false
                   videoBitrate: 1000
-                  encoderPreset: superfast
-                  audioPassthrough: true                                                               
+                  cpuUsageLevel: 3
+                  audioPassthrough: true
+
+  /api/admin/config/video/codec:
+    post:
+      summary: Set the video codec.
+      description: Sets the specific video codec that will be used for video encoding. Some codecs will support hardware acceleration. Not all codecs will be supported for all systems.
+      tags: ["Admin"]
+      security:
+        - AdminBasicAuth: []
+      responses:
+        '200':
+          $ref: "#/components/responses/BasicResponse"
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                value:
+                  description: The video codec to change to.
+                  type: string
+              example:
+                value: libx264
 
   /api/admin/config/s3:
       post: