1 import { getTargetBitrate } from '../../shared/models/videos'
2 import { AvailableEncoders, buildStreamSuffix, EncoderOptionsBuilder } from '../helpers/ffmpeg-utils'
3 import { ffprobePromise, getAudioStream, getMaxAudioBitrate, getVideoFileBitrate, getVideoStreamFromFile } from '../helpers/ffprobe-utils'
4 import { VIDEO_TRANSCODING_FPS } from '../initializers/constants'
6 // ---------------------------------------------------------------------------
7 // Available encoders profiles
8 // ---------------------------------------------------------------------------
11 // * https://slhck.info/video/2017/03/01/rate-control.html
12 // * https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate
14 const defaultX264VODOptionsBuilder: EncoderOptionsBuilder = async ({ input, resolution, fps }) => {
15 let targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
17 const probe = await ffprobePromise(input)
19 const videoStream = await getVideoStreamFromFile(input, probe)
21 return { outputOptions: [ ] }
24 // Don't transcode to an higher bitrate than the original file
25 const fileBitrate = await getVideoFileBitrate(input, probe)
26 targetBitrate = Math.min(targetBitrate, fileBitrate)
30 `-maxrate ${targetBitrate}`, `-bufsize ${targetBitrate * 2}`
35 const defaultX264LiveOptionsBuilder: EncoderOptionsBuilder = async ({ resolution, fps, streamNum }) => {
36 const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
40 `${buildStreamSuffix('-b:v', streamNum)} ${targetBitrate}`,
41 `-maxrate ${targetBitrate}`, `-bufsize ${targetBitrate * 2}`
46 const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNum }) => {
47 const parsedAudio = await getAudioStream(input)
49 // We try to reduce the ceiling bitrate by making rough matches of bitrates
50 // Of course this is far from perfect, but it might save some space in the end
52 const audioCodecName = parsedAudio.audioStream['codec_name']
54 const bitrate = getMaxAudioBitrate(audioCodecName, parsedAudio.bitrate)
56 if (bitrate !== undefined && bitrate !== -1) {
57 return { outputOptions: [ buildStreamSuffix('-b:a', streamNum), bitrate + 'k' ] }
60 return { copy: true, outputOptions: [] }
63 const defaultLibFDKAACVODOptionsBuilder: EncoderOptionsBuilder = ({ streamNum }) => {
64 return { outputOptions: [ buildStreamSuffix('-q:a', streamNum), '5' ] }
67 const availableEncoders: AvailableEncoders = {
70 default: defaultX264VODOptionsBuilder
73 default: defaultAACOptionsBuilder
76 default: defaultLibFDKAACVODOptionsBuilder
81 default: defaultX264LiveOptionsBuilder
84 default: defaultAACOptionsBuilder
89 // ---------------------------------------------------------------------------
95 // ---------------------------------------------------------------------------