-async function buildx264Command (command: ffmpeg.FfmpegCommand, options: TranscodeOptions) {
- let fps = await getVideoFileFPS(options.inputPath)
- if (
- // On small/medium resolutions, limit FPS
- options.resolution !== undefined &&
- options.resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
- fps > VIDEO_TRANSCODING_FPS.AVERAGE
- ) {
- // Get closest standard framerate by modulo: downsampling has to be done to a divisor of the nominal fps value
- fps = getClosestFramerateStandard(fps, 'STANDARD')
+// ---------------------------------------------------------------------------
+// Default options
+// ---------------------------------------------------------------------------
+
+function addDefaultEncoderGlobalParams (options: {
+ command: ffmpeg.FfmpegCommand
+}) {
+ const { command } = options
+
+ // avoid issues when transcoding some files: https://trac.ffmpeg.org/ticket/6375
+ command.outputOption('-max_muxing_queue_size 1024')
+ // strip all metadata
+ .outputOption('-map_metadata -1')
+ // NOTE: b-strategy 1 - heuristic algorithm, 16 is optimal B-frames for it
+ .outputOption('-b_strategy 1')
+ // NOTE: Why 16: https://github.com/Chocobozzz/PeerTube/pull/774. b-strategy 2 -> B-frames<16
+ .outputOption('-bf 16')
+ // allows import of source material with incompatible pixel formats (e.g. MJPEG video)
+ .outputOption('-pix_fmt yuv420p')
+}
+
+function addDefaultEncoderParams (options: {
+ command: ffmpeg.FfmpegCommand
+ encoder: 'libx264' | string
+ streamNum?: number
+ fps?: number
+}) {
+ const { command, encoder, fps, streamNum } = options
+
+ if (encoder === 'libx264') {
+ // 3.1 is the minimal resource allocation for our highest supported resolution
+ command.outputOption(buildStreamSuffix('-level:v', streamNum) + ' 3.1')
+
+ if (fps) {
+ // Keyframe interval of 2 seconds for faster seeking and resolution switching.
+ // https://streaminglearningcenter.com/blogs/whats-the-right-keyframe-interval.html
+ // https://superuser.com/a/908325
+ command.outputOption(buildStreamSuffix('-g:v', streamNum) + ' ' + (fps * 2))
+ }