X-Git-Url: https://git.immae.eu/?a=blobdiff_plain;f=server%2Fhelpers%2Fffmpeg-utils.ts;h=ced56b82daf6babfd7db43646ce72181ea029a7d;hb=541006e355c927a866d58cced016f48e139670d5;hp=4086335d7b31465110ef06debb1a25154367a3b0;hpb=3a6f351b255d21ec42578632600ba699885f350e;p=github%2FChocobozzz%2FPeerTube.git diff --git a/server/helpers/ffmpeg-utils.ts b/server/helpers/ffmpeg-utils.ts index 4086335d7..ced56b82d 100644 --- a/server/helpers/ffmpeg-utils.ts +++ b/server/helpers/ffmpeg-utils.ts @@ -1,10 +1,11 @@ import * as ffmpeg from 'fluent-ffmpeg' import { join } from 'path' import { VideoResolution } from '../../shared/models/videos' -import { CONFIG, VIDEO_TRANSCODING_FPS } from '../initializers' +import { CONFIG, VIDEO_TRANSCODING_FPS, FFMPEG_NICE } from '../initializers' import { unlinkPromise } from './core-utils' import { processImage } from './image-utils' import { logger } from './logger' +import { checkFFmpegEncoders } from '../initializers/checker' async function getVideoFileResolution (path: string) { const videoStream = await getVideoFileStream(path) @@ -55,7 +56,7 @@ async function generateImageFromVideoFile (fromPath: string, folder: string, ima try { await new Promise((res, rej) => { - ffmpeg(fromPath) + ffmpeg(fromPath, { niceness: FFMPEG_NICE.THUMBNAIL }) .on('error', rej) .on('end', () => res(imageName)) .thumbnail(options) @@ -83,12 +84,14 @@ type TranscodeOptions = { function transcode (options: TranscodeOptions) { return new Promise(async (res, rej) => { - let command = ffmpeg(options.inputPath) + let command = ffmpeg(options.inputPath, { niceness: FFMPEG_NICE.TRANSCODING }) .output(options.outputPath) - .videoCodec('libx264') - .outputOption('-threads ' + CONFIG.TRANSCODING.THREADS) - .outputOption('-movflags faststart') - // .outputOption('-crf 18') + .preset(standard) + + if (CONFIG.TRANSCODING.THREADS > 0) { + // if we don't set any threads ffmpeg will chose automatically + command = command.outputOption('-threads ' + CONFIG.TRANSCODING.THREADS) + } let fps = await getVideoFileFPS(options.inputPath) if (options.resolution !== undefined) { @@ -130,7 +133,8 @@ export { getDurationFromVideoFile, generateImageFromVideoFile, transcode, - getVideoFileFPS + getVideoFileFPS, + audio } // --------------------------------------------------------------------------- @@ -147,3 +151,136 @@ function getVideoFileStream (path: string) { }) }) } + +/** + * A slightly customised version of the 'veryfast' x264 preset + * + * The veryfast preset is right in the sweet spot of performance + * and quality. Superfast and ultrafast will give you better + * performance, but then quality is noticeably worse. + */ +function veryfast (_ffmpeg) { + _ffmpeg + .preset(standard) + .outputOption('-preset:v veryfast') + .outputOption(['--aq-mode=2', '--aq-strength=1.3']) + /* + MAIN reference: https://slhck.info/video/2017/03/01/rate-control.html + Our target situation is closer to a livestream than a stream, + since we want to reduce as much a possible the encoding burden, + altough not to the point of a livestream where there is a hard + constraint on the frames per second to be encoded. + + why '--aq-mode=2 --aq-strength=1.3' instead of '-profile:v main'? + Make up for most of the loss of grain and macroblocking + with less computing power. + */ +} + +/** + * A preset optimised for a stillimage audio video + */ +function audio (_ffmpeg) { + _ffmpeg + .preset(veryfast) + .outputOption('-tune stillimage') +} + +/** + * A toolbox to play with audio + */ +namespace audio { + export const get = (_ffmpeg, pos: number | string = 0) => { + // without position, ffprobe considers the last input only + // we make it consider the first input only + // if you pass a file path to pos, then ffprobe acts on that file directly + return new Promise<{ absolutePath: string, audioStream?: any }>((res, rej) => { + _ffmpeg.ffprobe(pos, (err,data) => { + if (err) return rej(err) + + if ('streams' in data) { + const audioStream = data['streams'].find(stream => stream['codec_type'] === 'audio') + if (audioStream) { + return res({ + absolutePath: data.format.filename, + audioStream + }) + } + } + return res({ absolutePath: data.format.filename }) + }) + }) + } + + export namespace bitrate { + export const baseKbitrate = 384 + + const toBits = (kbits: number): number => { return kbits * 8000 } + + export const aac = (bitrate: number): number => { + switch (true) { + case bitrate > toBits(baseKbitrate): + return baseKbitrate + default: + return -1 // we interpret it as a signal to copy the audio stream as is + } + } + + export const mp3 = (bitrate: number): number => { + /* + a 192kbit/sec mp3 doesn't hold as much information as a 192kbit/sec aac. + That's why, when using aac, we can go to lower kbit/sec. The equivalences + made here are not made to be accurate, especially with good mp3 encoders. + */ + switch (true) { + case bitrate <= toBits(192): + return 128 + case bitrate <= toBits(384): + return 256 + default: + return baseKbitrate + } + } + } +} + +/** + * Standard profile, with variable bitrate audio and faststart. + * + * As for the audio, quality '5' is the highest and ensures 96-112kbps/channel + * See https://trac.ffmpeg.org/wiki/Encode/AAC#fdk_vbr + */ +async function standard (_ffmpeg) { + let _bitrate = audio.bitrate.baseKbitrate + let localFfmpeg = _ffmpeg + .format('mp4') + .videoCodec('libx264') + .outputOption('-level 3.1') // 3.1 is the minimal ressource allocation for our highest supported resolution + .outputOption('-b_strategy 1') // NOTE: b-strategy 1 - heuristic algorythm, 16 is optimal B-frames for it + .outputOption('-bf 16') // NOTE: Why 16: https://github.com/Chocobozzz/PeerTube/pull/774. b-strategy 2 -> B-frames<16 + .outputOption('-map_metadata -1') // strip all metadata + .outputOption('-movflags faststart') + const _audio = await audio.get(localFfmpeg) + + if (!_audio.audioStream) { + return localFfmpeg.noAudio() + } + + // we try to reduce the ceiling bitrate by making rough correspondances of bitrates + // of course this is far from perfect, but it might save some space in the end + if (audio.bitrate[_audio.audioStream['codec_name']]) { + _bitrate = audio.bitrate[_audio.audioStream['codec_name']](_audio.audioStream['bit_rate']) + if (_bitrate === -1) { + return localFfmpeg.audioCodec('copy') + } + } + + // we favor VBR, if a good AAC encoder is available + if ((await checkFFmpegEncoders()).get('libfdk_aac')) { + return localFfmpeg + .audioCodec('libfdk_aac') + .audioQuality(5) + } + + return localFfmpeg.audioBitrate(_bitrate) +}