clipper/backend/media/get_audio.go

330 lines
9.3 KiB
Go

package media
import (
"bytes"
"context"
"encoding/binary"
"fmt"
"io"
"math"
"strconv"
"git.netflux.io/rob/clipper/config"
"git.netflux.io/rob/clipper/generated/store"
"go.uber.org/zap"
"golang.org/x/sync/errgroup"
)
type GetPeaksProgress struct {
PercentComplete float32
Peaks []int16
URL string
AudioFrames int64
}
type GetPeaksProgressReader interface {
Next() (GetPeaksProgress, error)
Close(string) error
}
// audioGetter manages getting and processing audio from Youtube.
type audioGetter struct {
store Store
youtube YoutubeClient
fileStore FileStore
commandFunc CommandFunc
workerPool *WorkerPool
config config.Config
logger *zap.SugaredLogger
}
// newAudioGetter returns a new audioGetter.
func newAudioGetter(store Store, youtube YoutubeClient, fileStore FileStore, commandFunc CommandFunc, workerPool *WorkerPool, config config.Config, logger *zap.SugaredLogger) *audioGetter {
return &audioGetter{
store: store,
youtube: youtube,
fileStore: fileStore,
commandFunc: commandFunc,
workerPool: workerPool,
config: config,
logger: logger,
}
}
// GetAudio gets the audio, processes it and uploads it to a file store. It
// returns a GetAudioProgressReader that can be used to poll progress reports
// and audio peaks.
//
// TODO: accept domain object instead
func (g *audioGetter) GetAudio(ctx context.Context, mediaSet store.MediaSet, numBins int) (GetPeaksProgressReader, error) {
video, err := g.youtube.GetVideoContext(ctx, mediaSet.YoutubeID)
if err != nil {
return nil, fmt.Errorf("error fetching video: %v", err)
}
format := video.Formats.FindByItag(int(mediaSet.AudioYoutubeItag))
if format == nil {
return nil, fmt.Errorf("error finding itag: %d", mediaSet.AudioYoutubeItag)
}
stream, _, err := g.youtube.GetStreamContext(ctx, video, format)
if err != nil {
return nil, fmt.Errorf("error fetching stream: %v", err)
}
audioProgressReader, err := newGetPeaksProgressReader(mediaSet.AudioFramesApprox, int(mediaSet.AudioChannels), numBins)
if err != nil {
return nil, fmt.Errorf("error building progress reader: %v", err)
}
s := &audioGetterState{
audioGetter: g,
getPeaksProgressReader: audioProgressReader,
}
go func() {
if err := g.workerPool.WaitForTask(ctx, func() error { return s.getAudio(ctx, stream, mediaSet) }); err != nil {
// the progress reader is closed inside the worker in the non-error case.
s.CloseWithError(err)
}
}()
return s, nil
}
// audioGetterState represents the state of an individual audio fetch.
type audioGetterState struct {
*audioGetter
*getPeaksProgressReader
}
func (s *audioGetterState) getAudio(ctx context.Context, r io.ReadCloser, mediaSet store.MediaSet) error {
streamWithProgress := newLogProgressReader(r, "audio", mediaSet.AudioContentLength, s.logger)
var stdErr bytes.Buffer
cmd := s.commandFunc(ctx, "ffmpeg", "-hide_banner", "-loglevel", "error", "-i", "-", "-f", rawAudioFormat, "-ar", strconv.Itoa(rawAudioSampleRate), "-acodec", rawAudioCodec, "-")
cmd.Stderr = &stdErr
// ffmpegWriter accepts encoded audio and pipes it to FFmpeg.
ffmpegWriter, err := cmd.StdinPipe()
if err != nil {
return fmt.Errorf("error getting stdin: %v", err)
}
uploadReader, uploadWriter := io.Pipe()
mw := io.MultiWriter(uploadWriter, ffmpegWriter)
// ffmpegReader delivers raw audio output from FFmpeg, and also writes it
// back to the progress reader.
var ffmpegReader io.Reader
if stdoutPipe, err := cmd.StdoutPipe(); err == nil {
ffmpegReader = io.TeeReader(stdoutPipe, s)
} else {
return fmt.Errorf("error getting stdout: %v", err)
}
var presignedAudioURL string
g, ctx := errgroup.WithContext(ctx)
// Upload the encoded audio.
g.Go(func() error {
// TODO: use mediaSet func to fetch key
key := fmt.Sprintf("media_sets/%s/audio.opus", mediaSet.ID)
_, encErr := s.fileStore.PutObject(ctx, key, uploadReader, "audio/opus")
if encErr != nil {
return fmt.Errorf("error uploading encoded audio: %v", encErr)
}
presignedAudioURL, encErr = s.fileStore.GetURL(ctx, key)
if encErr != nil {
return fmt.Errorf("error generating presigned URL: %v", encErr)
}
if _, encErr = s.store.SetEncodedAudioUploaded(ctx, store.SetEncodedAudioUploadedParams{
ID: mediaSet.ID,
AudioEncodedS3Key: sqlString(key),
}); encErr != nil {
return fmt.Errorf("error setting encoded audio uploaded: %v", encErr)
}
return nil
})
// Upload the raw audio.
g.Go(func() error {
// TODO: use mediaSet func to fetch key
key := fmt.Sprintf("media_sets/%s/audio.raw", mediaSet.ID)
bytesUploaded, rawErr := s.fileStore.PutObject(ctx, key, ffmpegReader, rawAudioMimeType)
if rawErr != nil {
return fmt.Errorf("error uploading raw audio: %v", rawErr)
}
if _, rawErr = s.store.SetRawAudioUploaded(ctx, store.SetRawAudioUploadedParams{
ID: mediaSet.ID,
AudioRawS3Key: sqlString(key),
AudioFrames: sqlInt64(bytesUploaded / SizeOfInt16 / int64(mediaSet.AudioChannels)),
}); rawErr != nil {
return fmt.Errorf("error setting raw audio uploaded: %v", rawErr)
}
return nil
})
g.Go(func() error {
if _, err := io.Copy(mw, streamWithProgress); err != nil {
return fmt.Errorf("error copying: %v", err)
}
// ignoring the following Close errors should be ok, as the Copy has
// already completed successfully.
if err := ffmpegWriter.Close(); err != nil {
s.logger.With("err", err).Warn("getAudio: unable to close ffmpegWriter")
}
if err := uploadWriter.Close(); err != nil {
s.logger.With("err", err).Warn("getAudio: unable to close pipeWriter")
}
if err := r.Close(); err != nil {
s.logger.With("err", err).Warn("getAudio: unable to close stream")
}
return nil
})
if err := cmd.Start(); err != nil {
return fmt.Errorf("error starting command: %v, output: %s", err, stdErr.String())
}
if err := g.Wait(); err != nil {
return fmt.Errorf("error uploading: %v", err)
}
if err := cmd.Wait(); err != nil {
return fmt.Errorf("error waiting for command: %v, output: %s", err, stdErr.String())
}
// Finally, close the progress reader so that the subsequent call to Next()
// returns the presigned URL and io.EOF.
s.Close(presignedAudioURL)
return nil
}
// getPeaksProgressReader accepts a byte stream containing little endian
// signed int16s and, given a target number of bins, emits a stream of peaks
// corresponding to each channel of the audio data.
type getPeaksProgressReader struct {
framesExpected int64
channels int
framesPerBin int
samples []int16
currPeaks []int16
currCount int
framesProcessed int64
url string
progress chan GetPeaksProgress
errorChan chan error
}
func newGetPeaksProgressReader(framesExpected int64, channels, numBins int) (*getPeaksProgressReader, error) {
if framesExpected <= 0 || channels <= 0 || numBins <= 0 {
return nil, fmt.Errorf("error creating audio progress reader (framesExpected = %d, channels = %d, numBins = %d)", framesExpected, channels, numBins)
}
return &getPeaksProgressReader{
channels: channels,
framesExpected: framesExpected,
framesPerBin: int(math.Ceil(float64(framesExpected) / float64(numBins))),
samples: make([]int16, 8_192),
currPeaks: make([]int16, channels),
progress: make(chan GetPeaksProgress),
errorChan: make(chan error, 1),
}, nil
}
func (w *getPeaksProgressReader) CloseWithError(err error) {
w.errorChan <- err
}
// Close cloes the reader and returns the provided URL to the calling code.
func (w *getPeaksProgressReader) Close(url string) error {
w.url = url
close(w.progress)
return nil
}
func (w *getPeaksProgressReader) Next() (GetPeaksProgress, error) {
for {
select {
case progress, ok := <-w.progress:
if !ok {
return GetPeaksProgress{
Peaks: w.currPeaks,
PercentComplete: w.percentComplete(),
URL: w.url,
AudioFrames: w.framesProcessed,
}, io.EOF
}
return progress, nil
case err := <-w.errorChan:
return GetPeaksProgress{}, fmt.Errorf("error waiting for progress: %v", err)
}
}
}
func (w *getPeaksProgressReader) Write(p []byte) (int, error) {
// expand our target slice if it is of insufficient size:
numSamples := len(p) / SizeOfInt16
if len(w.samples) < numSamples {
w.samples = append(w.samples, make([]int16, numSamples-len(w.samples))...)
}
samples := w.samples[:numSamples]
if err := binary.Read(bytes.NewReader(p), binary.LittleEndian, samples); err != nil {
return 0, fmt.Errorf("error parsing samples: %v", err)
}
for i := 0; i < len(samples); i += w.channels {
for j := 0; j < w.channels; j++ {
samp := samples[i+j]
if samp < 0 {
samp = -samp
}
if samp > w.currPeaks[j] {
w.currPeaks[j] = samp
}
}
w.currCount++
if w.currCount == w.framesPerBin {
w.nextBin()
}
}
w.framesProcessed += int64(len(samples) / w.channels)
return len(p), nil
}
func (w *getPeaksProgressReader) percentComplete() float32 {
return (float32(w.framesProcessed) / float32(w.framesExpected)) * 100.0
}
func (w *getPeaksProgressReader) nextBin() {
var progress GetPeaksProgress
progress.Peaks = append(progress.Peaks, w.currPeaks...)
progress.PercentComplete = w.percentComplete()
w.progress <- progress
w.currCount = 0
for i := 0; i < len(w.currPeaks); i++ {
w.currPeaks[i] = 0
}
}