import { logger } from '@server/helpers/logger' import { getTargetBitrate, VideoResolution } from '../../shared/models/videos' import { AvailableEncoders, buildStreamSuffix, EncoderOptionsBuilder } from '../helpers/ffmpeg-utils' import { canDoQuickAudioTranscode, ffprobePromise, getAudioStream, getMaxAudioBitrate, getVideoFileBitrate, getVideoStreamFromFile } from '../helpers/ffprobe-utils' import { VIDEO_TRANSCODING_FPS } from '../initializers/constants' /** * * Available encoders and profiles for the transcoding jobs * These functions are used by ffmpeg-utils that will get the encoders and options depending on the chosen profile * */ // Resources: // * https://slhck.info/video/2017/03/01/rate-control.html // * https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate const defaultX264VODOptionsBuilder: EncoderOptionsBuilder = async ({ input, resolution, fps }) => { const targetBitrate = await buildTargetBitrate({ input, resolution, fps }) if (!targetBitrate) return { outputOptions: [ ] } return { outputOptions: [ `-r ${fps}`, `-maxrate ${targetBitrate}`, `-bufsize ${targetBitrate * 2}` ] } } const defaultX264LiveOptionsBuilder: EncoderOptionsBuilder = async ({ resolution, fps, streamNum }) => { const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS) return { outputOptions: [ `${buildStreamSuffix('-r:v', streamNum)} ${fps}`, `${buildStreamSuffix('-b:v', streamNum)} ${targetBitrate}`, `-maxrate ${targetBitrate}`, `-bufsize ${targetBitrate * 2}` ] } } const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNum }) => { const probe = await ffprobePromise(input) if (await canDoQuickAudioTranscode(input, probe)) { logger.debug('Copy audio stream %s by AAC encoder.', input) return { copy: true, outputOptions: [] } } const parsedAudio = await getAudioStream(input, probe) // We try to reduce the ceiling bitrate by making rough matches of bitrates // Of course this is far from perfect, but it might save some space in the end const audioCodecName = parsedAudio.audioStream['codec_name'] const bitrate = getMaxAudioBitrate(audioCodecName, parsedAudio.bitrate) logger.debug('Calculating audio bitrate of %s by AAC encoder.', input, { bitrate: parsedAudio.bitrate, audioCodecName }) if (bitrate !== undefined && bitrate !== -1) { return { outputOptions: [ buildStreamSuffix('-b:a', streamNum), bitrate + 'k' ] } } return { outputOptions: [ ] } } const defaultLibFDKAACVODOptionsBuilder: EncoderOptionsBuilder = ({ streamNum }) => { return { outputOptions: [ buildStreamSuffix('-q:a', streamNum), '5' ] } } const availableEncoders: AvailableEncoders = { vod: { libx264: { default: defaultX264VODOptionsBuilder }, aac: { default: defaultAACOptionsBuilder }, libfdk_aac: { default: defaultLibFDKAACVODOptionsBuilder } }, live: { libx264: { default: defaultX264LiveOptionsBuilder }, aac: { default: defaultAACOptionsBuilder } } } // --------------------------------------------------------------------------- export { availableEncoders } // --------------------------------------------------------------------------- async function buildTargetBitrate (options: { input: string resolution: VideoResolution fps: number }) { const { input, resolution, fps } = options const probe = await ffprobePromise(input) const videoStream = await getVideoStreamFromFile(input, probe) if (!videoStream) return undefined const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS) // Don't transcode to an higher bitrate than the original file const fileBitrate = await getVideoFileBitrate(input, probe) return Math.min(targetBitrate, fileBitrate) }