Files
navidrome/core/transcode/transcode.go

360 lines
12 KiB
Go

package transcode
import (
"context"
"errors"
"fmt"
"strings"
"time"
"github.com/navidrome/navidrome/core/auth"
"github.com/navidrome/navidrome/log"
"github.com/navidrome/navidrome/model"
)
const (
tokenTTL = 12 * time.Hour
defaultBitrate = 256 // kbps
)
func NewDecider(ds model.DataStore) Decider {
return &deciderService{
ds: ds,
}
}
type deciderService struct {
ds model.DataStore
}
func (s *deciderService) MakeDecision(ctx context.Context, mf *model.MediaFile, clientInfo *ClientInfo) (*Decision, error) {
decision := &Decision{
MediaID: mf.ID,
}
sourceBitrate := mf.BitRate // kbps
log.Trace(ctx, "Making transcode decision", "mediaID", mf.ID, "container", mf.Suffix,
"codec", mf.AudioCodec(), "bitrate", sourceBitrate, "channels", mf.Channels,
"sampleRate", mf.SampleRate, "lossless", mf.IsLossless(), "client", clientInfo.Name)
// Build source stream details
decision.SourceStream = buildSourceStream(mf)
// Check global bitrate constraint first.
if clientInfo.MaxAudioBitrate > 0 && sourceBitrate > clientInfo.MaxAudioBitrate {
log.Trace(ctx, "Global bitrate constraint exceeded, skipping direct play",
"sourceBitrate", sourceBitrate, "maxAudioBitrate", clientInfo.MaxAudioBitrate)
decision.TranscodeReasons = append(decision.TranscodeReasons, "audio bitrate not supported")
// Skip direct play profiles entirely — global constraint fails
} else {
// Try direct play profiles, collecting reasons for each failure
for _, profile := range clientInfo.DirectPlayProfiles {
if reason := s.checkDirectPlayProfile(mf, sourceBitrate, &profile, clientInfo); reason == "" {
decision.CanDirectPlay = true
decision.TranscodeReasons = nil // Clear any previously collected reasons
break
} else {
decision.TranscodeReasons = append(decision.TranscodeReasons, reason)
}
}
}
// If direct play is possible, we're done
if decision.CanDirectPlay {
log.Debug(ctx, "Transcode decision: direct play", "mediaID", mf.ID, "container", mf.Suffix, "codec", mf.AudioCodec())
return decision, nil
}
// Try transcoding profiles (in order of preference)
for _, profile := range clientInfo.TranscodingProfiles {
if ts, transcodeFormat := s.computeTranscodedStream(ctx, mf, sourceBitrate, &profile, clientInfo); ts != nil {
decision.CanTranscode = true
decision.TargetFormat = transcodeFormat
decision.TargetBitrate = ts.Bitrate
decision.TargetChannels = ts.Channels
decision.TargetSampleRate = ts.SampleRate
decision.TargetBitDepth = ts.BitDepth
decision.TranscodeStream = ts
break
}
}
if decision.CanTranscode {
log.Debug(ctx, "Transcode decision: transcode", "mediaID", mf.ID,
"targetFormat", decision.TargetFormat, "targetBitrate", decision.TargetBitrate,
"targetChannels", decision.TargetChannels, "reasons", decision.TranscodeReasons)
}
// If neither direct play nor transcode is possible
if !decision.CanDirectPlay && !decision.CanTranscode {
decision.ErrorReason = "no compatible playback profile found"
log.Warn(ctx, "Transcode decision: no compatible profile", "mediaID", mf.ID,
"container", mf.Suffix, "codec", mf.AudioCodec(), "reasons", decision.TranscodeReasons)
}
return decision, nil
}
func buildSourceStream(mf *model.MediaFile) StreamDetails {
return StreamDetails{
Container: mf.Suffix,
Codec: mf.AudioCodec(),
Bitrate: mf.BitRate,
SampleRate: mf.SampleRate,
BitDepth: mf.BitDepth,
Channels: mf.Channels,
Duration: mf.Duration,
Size: mf.Size,
IsLossless: mf.IsLossless(),
}
}
// checkDirectPlayProfile returns "" if the profile matches (direct play OK),
// or a typed reason string if it doesn't match.
func (s *deciderService) checkDirectPlayProfile(mf *model.MediaFile, sourceBitrate int, profile *DirectPlayProfile, clientInfo *ClientInfo) string {
// Check protocol (only http for now)
if len(profile.Protocols) > 0 && !containsIgnoreCase(profile.Protocols, ProtocolHTTP) {
return "protocol not supported"
}
// Check container
if len(profile.Containers) > 0 && !matchesContainer(mf.Suffix, profile.Containers) {
return "container not supported"
}
// Check codec
if len(profile.AudioCodecs) > 0 && !matchesCodec(mf.AudioCodec(), profile.AudioCodecs) {
return "audio codec not supported"
}
// Check channels
if profile.MaxAudioChannels > 0 && mf.Channels > profile.MaxAudioChannels {
return "audio channels not supported"
}
// Check codec-specific limitations
for _, codecProfile := range clientInfo.CodecProfiles {
if strings.EqualFold(codecProfile.Type, CodecProfileTypeAudio) && matchesCodec(mf.AudioCodec(), []string{codecProfile.Name}) {
if reason := checkLimitations(mf, sourceBitrate, codecProfile.Limitations); reason != "" {
return reason
}
}
}
return ""
}
// computeTranscodedStream attempts to build a valid transcoded stream for the given profile.
// Returns the stream details and the internal transcoding format (which may differ from the
// response container when a codec fallback occurs, e.g., "mp4"→"aac").
// Returns nil, "" if the profile cannot produce a valid output.
func (s *deciderService) computeTranscodedStream(ctx context.Context, mf *model.MediaFile, sourceBitrate int, profile *Profile, clientInfo *ClientInfo) (*StreamDetails, string) {
// Check protocol (only http for now)
if profile.Protocol != "" && !strings.EqualFold(profile.Protocol, ProtocolHTTP) {
log.Trace(ctx, "Skipping transcoding profile: unsupported protocol", "protocol", profile.Protocol)
return nil, ""
}
responseContainer, targetFormat := s.resolveTargetFormat(ctx, profile)
if targetFormat == "" {
return nil, ""
}
targetIsLossless := isLosslessFormat(targetFormat)
// Reject lossy to lossless conversion
if !mf.IsLossless() && targetIsLossless {
log.Trace(ctx, "Skipping transcoding profile: lossy to lossless not allowed", "targetFormat", targetFormat)
return nil, ""
}
ts := &StreamDetails{
Container: responseContainer,
Codec: strings.ToLower(profile.AudioCodec),
SampleRate: normalizeSourceSampleRate(mf.SampleRate, mf.AudioCodec()),
Channels: mf.Channels,
BitDepth: normalizeSourceBitDepth(mf.BitDepth, mf.AudioCodec()),
IsLossless: targetIsLossless,
}
if ts.Codec == "" {
ts.Codec = targetFormat
}
// Apply codec-intrinsic sample rate adjustments before codec profile limitations
if fixedRate := codecFixedOutputSampleRate(ts.Codec); fixedRate > 0 {
ts.SampleRate = fixedRate
}
if maxRate := codecMaxSampleRate(ts.Codec); maxRate > 0 && ts.SampleRate > maxRate {
ts.SampleRate = maxRate
}
// Determine target bitrate (all in kbps)
if ok := s.computeBitrate(ctx, mf, sourceBitrate, targetFormat, targetIsLossless, clientInfo, ts); !ok {
return nil, ""
}
// Apply MaxAudioChannels from the transcoding profile
if profile.MaxAudioChannels > 0 && mf.Channels > profile.MaxAudioChannels {
ts.Channels = profile.MaxAudioChannels
}
// Apply codec profile limitations to the TARGET codec
if ok := s.applyCodecLimitations(ctx, sourceBitrate, targetFormat, targetIsLossless, clientInfo, ts); !ok {
return nil, ""
}
return ts, targetFormat
}
// resolveTargetFormat determines the response container and internal target format
// by looking up transcoding configs. Returns ("", "") if no config found.
func (s *deciderService) resolveTargetFormat(ctx context.Context, profile *Profile) (responseContainer, targetFormat string) {
responseContainer = strings.ToLower(profile.Container)
targetFormat = responseContainer
if targetFormat == "" {
targetFormat = strings.ToLower(profile.AudioCodec)
responseContainer = targetFormat
}
// Try the container first, then fall back to the audioCodec (e.g. "ogg" → "opus", "mp4" → "aac").
_, err := s.ds.Transcoding(ctx).FindByFormat(targetFormat)
if errors.Is(err, model.ErrNotFound) && profile.AudioCodec != "" && !strings.EqualFold(targetFormat, profile.AudioCodec) {
codec := strings.ToLower(profile.AudioCodec)
log.Trace(ctx, "No transcoding config for container, trying audioCodec", "container", targetFormat, "audioCodec", codec)
_, err = s.ds.Transcoding(ctx).FindByFormat(codec)
if err == nil {
targetFormat = codec
}
}
if err != nil {
if !errors.Is(err, model.ErrNotFound) {
log.Error(ctx, "Error looking up transcoding config", "format", targetFormat, err)
} else {
log.Trace(ctx, "Skipping transcoding profile: no transcoding config", "targetFormat", targetFormat)
}
return "", ""
}
return responseContainer, targetFormat
}
// computeBitrate determines the target bitrate for the transcoded stream.
// Returns false if the profile should be rejected.
func (s *deciderService) computeBitrate(ctx context.Context, mf *model.MediaFile, sourceBitrate int, targetFormat string, targetIsLossless bool, clientInfo *ClientInfo, ts *StreamDetails) bool {
if mf.IsLossless() {
if !targetIsLossless {
if clientInfo.MaxTranscodingAudioBitrate > 0 {
ts.Bitrate = clientInfo.MaxTranscodingAudioBitrate
} else {
ts.Bitrate = defaultBitrate
}
} else {
if clientInfo.MaxAudioBitrate > 0 && sourceBitrate > clientInfo.MaxAudioBitrate {
log.Trace(ctx, "Skipping transcoding profile: lossless target exceeds bitrate limit",
"targetFormat", targetFormat, "sourceBitrate", sourceBitrate, "maxAudioBitrate", clientInfo.MaxAudioBitrate)
return false
}
}
} else {
ts.Bitrate = sourceBitrate
}
// Apply maxAudioBitrate as final cap
if clientInfo.MaxAudioBitrate > 0 && ts.Bitrate > 0 && ts.Bitrate > clientInfo.MaxAudioBitrate {
ts.Bitrate = clientInfo.MaxAudioBitrate
}
return true
}
// applyCodecLimitations applies codec profile limitations to the transcoded stream.
// Returns false if the profile should be rejected.
func (s *deciderService) applyCodecLimitations(ctx context.Context, sourceBitrate int, targetFormat string, targetIsLossless bool, clientInfo *ClientInfo, ts *StreamDetails) bool {
targetCodec := ts.Codec
for _, codecProfile := range clientInfo.CodecProfiles {
if !strings.EqualFold(codecProfile.Type, CodecProfileTypeAudio) {
continue
}
if !matchesCodec(targetCodec, []string{codecProfile.Name}) {
continue
}
for _, lim := range codecProfile.Limitations {
result := applyLimitation(sourceBitrate, &lim, ts)
if strings.EqualFold(lim.Name, LimitationAudioBitrate) && targetIsLossless && result == adjustAdjusted {
log.Trace(ctx, "Skipping transcoding profile: cannot adjust bitrate for lossless target",
"targetFormat", targetFormat, "codec", targetCodec, "limitation", lim.Name)
return false
}
if result == adjustCannotFit {
log.Trace(ctx, "Skipping transcoding profile: codec limitation cannot be satisfied",
"targetFormat", targetFormat, "codec", targetCodec, "limitation", lim.Name,
"comparison", lim.Comparison, "values", lim.Values)
return false
}
}
}
return true
}
func (s *deciderService) CreateTranscodeParams(decision *Decision) (string, error) {
exp := time.Now().Add(tokenTTL)
claims := map[string]any{
"mid": decision.MediaID,
"dp": decision.CanDirectPlay,
}
if decision.CanTranscode && decision.TargetFormat != "" {
claims["fmt"] = decision.TargetFormat
claims["br"] = decision.TargetBitrate
if decision.TargetChannels > 0 {
claims["ch"] = decision.TargetChannels
}
if decision.TargetSampleRate > 0 {
claims["sr"] = decision.TargetSampleRate
}
if decision.TargetBitDepth > 0 {
claims["bd"] = decision.TargetBitDepth
}
}
return auth.CreateExpiringPublicToken(exp, claims)
}
func (s *deciderService) ParseTranscodeParams(token string) (*Params, error) {
claims, err := auth.Validate(token)
if err != nil {
return nil, err
}
params := &Params{}
// Required claims
mid, ok := claims["mid"].(string)
if !ok || mid == "" {
return nil, fmt.Errorf("invalid transcode token: missing media ID")
}
params.MediaID = mid
dp, ok := claims["dp"].(bool)
if !ok {
return nil, fmt.Errorf("invalid transcode token: missing direct play flag")
}
params.DirectPlay = dp
// Optional claims (legitimately absent for direct-play tokens)
if f, ok := claims["fmt"].(string); ok {
params.TargetFormat = f
}
if br, ok := claims["br"].(float64); ok {
params.TargetBitrate = int(br)
}
if ch, ok := claims["ch"].(float64); ok {
params.TargetChannels = int(ch)
}
if sr, ok := claims["sr"].(float64); ok {
params.TargetSampleRate = int(sr)
}
if bd, ok := claims["bd"].(float64); ok {
params.TargetBitDepth = int(bd)
}
return params, nil
}