strip-beats/media/ffmpeg.go

package media

import (
	"errors"
	"fmt"
	p "path/filepath"
	"strconv"
	s "strings"

	"codeberg.org/danjones000/strip-beats/config"
	t "codeberg.org/danjones000/strip-beats/media/tags"
	"codeberg.org/danjones000/strip-beats/utils"
	"github.com/google/uuid"
	ffmpeg "github.com/u2takey/ffmpeg-go"
)

func ConvertAndTag(in Probe, tags t.Tags) (string, error) {
	st := in.GetFirstAcceptableAudio()
	if st == nil {
		st = in.GetFirstAudio()
	}
	if st == nil {
		return "", errors.New("Can't find an audio stream")
	}

	conf := config.GetConfig()
	codec := utils.Tern(st.isAcceptableCodec(), "copy", conf.FfEncoder)
	target := utils.Tern(st.isAcceptableCodec(), st.CodecName, conf.Codec)

	base := p.Base(in.Format.Path)
	ext := p.Ext(base)
	base = s.TrimSuffix(base, ext)
	ext = conf.CodecExt[target]

	out := p.Join(conf.SavePath, base+"."+ext)

	input := ffmpeg.Input(in.Format.Path).Get(strconv.Itoa(st.Index))
	args := ffmpeg.KwArgs{"c:a": codec}
	output := input.Output(out, args, getMetadataArgs(ext, tags)).GlobalArgs("-y")

	return out, output.Run()
}

func getMetadataArgs(ext string, tags t.Tags) ffmpeg.KwArgs {
	var meta []string
	args := ffmpeg.KwArgs{}
	switch ext {
	case "opus":
		fallthrough
	case "flac":
		fallthrough
	case "ogg":
		meta = append(meta, mapMetaKeys(getOggMeta(tags))...)
	case "m4a":
		fallthrough
	case "mp4":
		meta = append(meta, mapMetaKeys(getMp4Meta(tags))...)
	case "mp3":
		// @todo meta = append(meta, mapMetaKeys(getMp3Meta(tags))...)
	}

	meta = append(meta, "comment=Processed by "+config.UserAgent)
	args["metadata"] = meta
	return args
}

func mapMetaKeys(meta map[string]string) []string {
	out := []string{}
	for k, v := range meta {
		if v != "" {
			out = append(out, fmt.Sprintf("%s=%s", k, v))
		}
	}
	return out
}

func getOggMeta(tags t.Tags) map[string]string {
	meta := map[string]string{}
	meta["TITLE"] = tags.Title
	meta["ARTIST"] = tags.Artist
	meta["ALBUM_ARTIST"] = tags.AlbumArtist
	meta["ALBUMARTIST"] = tags.AlbumArtist
	meta["ALBUM"] = tags.Album
	meta["DATE"] = tags.Date
	year, _, _ := s.Cut(tags.Date, "-")
	meta["YEAR"] = year
	meta["URL"] = tags.Url
	meta["PURL"] = tags.Url
	meta["URI"] = tags.Url
	meta["ARTISTSORT"] = tags.ArtistSort
	meta["ALBUMARTISTSORT"] = tags.AlbumArtistSort
	meta["RELEASECOUNTRY"] = tags.ReleaseCountry
	meta["LABEL"] = tags.Label
	meta["GENRE"] = tags.Genre
	meta["DISC"] = utils.Tern(tags.Disc > 0, strconv.Itoa(tags.Disc), "")
	meta["DISCTOTAL"] = utils.Tern(tags.DiscCount > 0, strconv.Itoa(tags.DiscCount), "")
	meta["TRACK"] = utils.Tern(tags.Track > 0, strconv.Itoa(tags.Track), "")
	meta["TRACKTOTAL"] = utils.Tern(tags.TrackCount > 0, strconv.Itoa(tags.TrackCount), "")
	if tags.AcoustidId != uuid.Nil {
		meta["ACOUSTID_ID"] = tags.AcoustidId.String()
	}
	if tags.MusicbrainzReleaseGroupId != uuid.Nil {
		meta["MUSICBRAINZ_RELEASEGROUPID"] = tags.MusicbrainzReleaseGroupId.String()
	}
	if tags.MusicbrainzAlbumId != uuid.Nil {
		meta["MUSICBRAINZ_ALBUMID"] = tags.MusicbrainzAlbumId.String()
	}
	if tags.MusicbrainzAlbumArtistId != uuid.Nil {
		meta["MUSICBRAINZ_ALBUMARTISTID"] = tags.MusicbrainzAlbumArtistId.String()
	}
	if tags.MusicbrainzRecordingId != uuid.Nil {
		meta["MUSICBRAINZ_RECORDINGID"] = tags.MusicbrainzRecordingId.String()
	}
	if tags.MusicBrainzLabelId != uuid.Nil {
		meta["MUSICBRAINZ_LABELID"] = tags.MusicBrainzLabelId.String()
	}

	return meta
}

func getMp4Meta(tags t.Tags) map[string]string {
	meta := map[string]string{}
	meta["title"] = tags.Title
	meta["artist"] = tags.Artist
	meta["album_artist"] = tags.AlbumArtist
	meta["album"] = tags.Album
	year, _, _ := s.Cut(tags.Date, "-")
	meta["year"] = year
	meta["description"] = tags.Url
	meta["genre"] = tags.Genre
	meta["network"] = tags.Label
	if tags.Disc > 0 {
		meta["disc"] = fmt.Sprintf("%d", tags.Disc) + utils.Tern(tags.DiscCount > 0, fmt.Sprintf("/%d", tags.DiscCount), "")
	}
	if tags.Track > 0 {
		meta["track"] = fmt.Sprintf("%d", tags.Track) + utils.Tern(tags.TrackCount > 0, fmt.Sprintf("/%d", tags.TrackCount), "")
	}

	return meta
}

func TrimWithFade(in Probe, out string, start, stop, up, down float64) error {
	// -ss (start) -t (end) -af afade=t=in:st=(start):d=(up),afade=t=out:st=(downstart):d=(down)
	st := in.GetFirstAcceptableAudio()
	if st == nil {
		return errors.New("Can't find an audio stream")
	}
	args := ffmpeg.KwArgs{"c:a": "copy"}
	if start != 0 {
		args["ss"] = start
	}
	if stop != 0 {
		end := stop - start
		args["t"] = end
	} else {
		stop = st.Duration
	}

	input := ffmpeg.Input(in.Format.Path).Get(strconv.Itoa(st.Index))
	if up != 0 {
		args["c:a"] = config.GetConfig().FfEncoder
		input = input.Filter("afade", ffmpeg.Args{
			"t=in",
			fmt.Sprintf("st=%v", start),
			fmt.Sprintf("d=%v", up)})
	}

	if down != 0 {
		args["c:a"] = config.GetConfig().FfEncoder
		downstart := stop - down
		input = input.Filter("afade", ffmpeg.Args{
			"t=out",
			fmt.Sprintf("st=%v", downstart),
			fmt.Sprintf("d=%v", down)})
	}
	output := input.Output(out, args).GlobalArgs("-y")
	// @todo out should be stdout
	return output.Run()
}

func Trim(in Probe, out string, start, stop float64) error {
	return TrimWithFade(in, out, start, stop, 0, 0)
}

func Fade(in Probe, out string, up, down float64) error {
	return TrimWithFade(in, out, 0, 0, up, down)
}