import * as ffmpeg from 'fluent-ffmpeg' import { join } from 'path' import { getTargetBitrate, VideoResolution } from '../../shared/models/videos' import { CONFIG, FFMPEG_NICE, VIDEO_TRANSCODING_FPS } from '../initializers' import { processImage } from './image-utils' import { logger } from './logger' import { checkFFmpegEncoders } from '../initializers/checker-before-init' import { remove } from 'fs-extra' function computeResolutionsToTranscode (videoFileHeight: number) { const resolutionsEnabled: number[] = [] const configResolutions = CONFIG.TRANSCODING.RESOLUTIONS // Put in the order we want to proceed jobs const resolutions = [ VideoResolution.H_480P, VideoResolution.H_360P, VideoResolution.H_720P, VideoResolution.H_240P, VideoResolution.H_1080P ] for (const resolution of resolutions) { if (configResolutions[ resolution + 'p' ] === true && videoFileHeight > resolution) { resolutionsEnabled.push(resolution) } } return resolutionsEnabled } async function getVideoFileResolution (path: string) { const videoStream = await getVideoFileStream(path) return { videoFileResolution: Math.min(videoStream.height, videoStream.width), isPortraitMode: videoStream.height > videoStream.width } } async function getVideoFileFPS (path: string) { const videoStream = await getVideoFileStream(path) for (const key of [ 'r_frame_rate' , 'avg_frame_rate' ]) { const valuesText: string = videoStream[key] if (!valuesText) continue const [ frames, seconds ] = valuesText.split('/') if (!frames || !seconds) continue const result = parseInt(frames, 10) / parseInt(seconds, 10) if (result > 0) return Math.round(result) } return 0 } async function getVideoFileBitrate (path: string) { return new Promise((res, rej) => { ffmpeg.ffprobe(path, (err, metadata) => { if (err) return rej(err) return res(metadata.format.bit_rate) }) }) } function getDurationFromVideoFile (path: string) { return new Promise((res, rej) => { ffmpeg.ffprobe(path, (err, metadata) => { if (err) return rej(err) return res(Math.floor(metadata.format.duration)) }) }) } async function generateImageFromVideoFile (fromPath: string, folder: string, imageName: string, size: { width: number, height: number }) { const pendingImageName = 'pending-' + imageName const options = { filename: pendingImageName, count: 1, folder } const pendingImagePath = join(folder, pendingImageName) try { await new Promise((res, rej) => { ffmpeg(fromPath, { niceness: FFMPEG_NICE.THUMBNAIL }) .on('error', rej) .on('end', () => res(imageName)) .thumbnail(options) }) const destination = join(folder, imageName) await processImage({ path: pendingImagePath }, destination, size) } catch (err) { logger.error('Cannot generate image from video %s.', fromPath, { err }) try { await remove(pendingImagePath) } catch (err) { logger.debug('Cannot remove pending image path after generation error.', { err }) } } } type TranscodeOptions = { inputPath: string outputPath: string resolution?: VideoResolution isPortraitMode?: boolean } function transcode (options: TranscodeOptions) { return new Promise(async (res, rej) => { try { let fps = await getVideoFileFPS(options.inputPath) // On small/medium resolutions, limit FPS if ( options.resolution !== undefined && options.resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN && fps > VIDEO_TRANSCODING_FPS.AVERAGE ) { fps = VIDEO_TRANSCODING_FPS.AVERAGE } let command = ffmpeg(options.inputPath, { niceness: FFMPEG_NICE.TRANSCODING }) .output(options.outputPath) command = await presetH264(command, options.resolution, fps) if (CONFIG.TRANSCODING.THREADS > 0) { // if we don't set any threads ffmpeg will chose automatically command = command.outputOption('-threads ' + CONFIG.TRANSCODING.THREADS) } if (options.resolution !== undefined) { // '?x720' or '720x?' for example const size = options.isPortraitMode === true ? `${options.resolution}x?` : `?x${options.resolution}` command = command.size(size) } if (fps) { // Hard FPS limits if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = VIDEO_TRANSCODING_FPS.MAX else if (fps < VIDEO_TRANSCODING_FPS.MIN) fps = VIDEO_TRANSCODING_FPS.MIN command = command.withFPS(fps) } command .on('error', (err, stdout, stderr) => { logger.error('Error in transcoding job.', { stdout, stderr }) return rej(err) }) .on('end', res) .run() } catch (err) { return rej(err) } }) } // --------------------------------------------------------------------------- export { getVideoFileResolution, getDurationFromVideoFile, generateImageFromVideoFile, transcode, getVideoFileFPS, computeResolutionsToTranscode, audio, getVideoFileBitrate } // --------------------------------------------------------------------------- function getVideoFileStream (path: string) { return new Promise((res, rej) => { ffmpeg.ffprobe(path, (err, metadata) => { if (err) return rej(err) const videoStream = metadata.streams.find(s => s.codec_type === 'video') if (!videoStream) throw new Error('Cannot find video stream of ' + path) return res(videoStream) }) }) } /** * 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. */ async function presetH264VeryFast (command: ffmpeg.FfmpegCommand, resolution: VideoResolution, fps: number): Promise { let localCommand = await presetH264(command, resolution, fps) localCommand = localCommand.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. */ return localCommand } /** * A preset optimised for a stillimage audio video */ async function presetStillImageWithAudio ( command: ffmpeg.FfmpegCommand, resolution: VideoResolution, fps: number ): Promise { let localCommand = await presetH264VeryFast(command, resolution, fps) localCommand = localCommand.outputOption('-tune stillimage') return localCommand } /** * A toolbox to play with audio */ namespace audio { export const get = (option: ffmpeg.FfmpegCommand | string) => { // 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) => { function parseFfprobe (err: any, data: ffmpeg.FfprobeData) { 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 }) } if (typeof option === 'string') { return ffmpeg.ffprobe(option, parseFfprobe) } return option.ffprobe(parseFfprobe) }) } export namespace bitrate { 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 presetH264 (command: ffmpeg.FfmpegCommand, resolution: VideoResolution, fps: number): Promise { let localCommand = command .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('-pix_fmt yuv420p') // allows import of source material with incompatible pixel formats (e.g. MJPEG video) .outputOption('-map_metadata -1') // strip all metadata .outputOption('-movflags faststart') const parsedAudio = await audio.get(localCommand) if (!parsedAudio.audioStream) { localCommand = localCommand.noAudio() } else if ((await checkFFmpegEncoders()).get('libfdk_aac')) { // we favor VBR, if a good AAC encoder is available localCommand = localCommand .audioCodec('libfdk_aac') .audioQuality(5) } else { // 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 const audioCodecName = parsedAudio.audioStream[ 'codec_name' ] let bitrate: number if (audio.bitrate[ audioCodecName ]) { bitrate = audio.bitrate[ audioCodecName ](parsedAudio.audioStream[ 'bit_rate' ]) if (bitrate === -1) localCommand = localCommand.audioCodec('copy') else if (bitrate !== undefined) localCommand = localCommand.audioBitrate(bitrate) } } // Constrained Encoding (VBV) // https://slhck.info/video/2017/03/01/rate-control.html // https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS) localCommand = localCommand.outputOptions([`-maxrate ${ targetBitrate }`, `-bufsize ${ targetBitrate * 2 }`]) // 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 localCommand = localCommand.outputOption(`-g ${ fps * 2 }`) return localCommand }