musicutil/utils/transcoder/transcode_presets.go

package transcoder

import (
	"fmt"
)

type Preset struct {
	Name   string           `json:"name"`
	Config *TranscodeConfig `json:"config"`
}

var TranscodePresets map[string][]*Preset

func add_to_presets(category string, items []*Preset) {
	if _, ok := TranscodePresets[category]; !ok {
		TranscodePresets[category] = make([]*Preset, 0)
	}
	for _, preset := range items {
		TranscodePresets[category] = append(TranscodePresets[category], preset)
	}
}

func add_mp3_presets() {
	mp3_presets := make([]*Preset, 0)

	mp3_bitrates := []int{8, 16, 24, 32, 40, 48, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320}

	for _, bitrate := range mp3_bitrates {
		mp3_presets = append(mp3_presets, &Preset{
			Name: fmt.Sprintf("mp3-%dk", bitrate),
			Config: &TranscodeConfig{
				Encoder:       "libmp3lame",
				Container:     "mp3",
				FileExtension: "mp3",
				UseBitrate:    true,
				Bitrate:       fmt.Sprintf("%dk", bitrate),
			},
		})
	}

	mp3_qualities := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
	for _, quality := range mp3_qualities {
		mp3_presets = append(mp3_presets, &Preset{
			Name: fmt.Sprintf("mp3-v%d", quality),
			Config: &TranscodeConfig{
				Encoder:       "libmp3lame",
				Container:     "mp3",
				FileExtension: "mp3",
				UseQuality:    true,
				Quality:       fmt.Sprintf("%d", quality),
			},
		})
	}

	add_to_presets("mp3", mp3_presets)
}

func add_opus_presets() {
	opus_presets := make([]*Preset, 0)

	opus_bitrates := []int{16, 24, 32, 64, 96, 128, 256}

	for _, bitrate := range opus_bitrates {
		opus_presets = append(opus_presets, &Preset{
			Name: fmt.Sprintf("opus-%dk", bitrate),
			Config: &TranscodeConfig{
				Encoder:       "libopus",
				Container:     "ogg",
				FileExtension: "opus",
				UseBitrate:    true,
				Bitrate:       fmt.Sprintf("%dk", bitrate),
			},
		})
	}

	add_to_presets("opus", opus_presets)
}

func add_vorbis_presets() {
	vorbis_presets := make([]*Preset, 0)

	vorbis_qualities := []int{-2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

	for _, quality := range vorbis_qualities {
		vorbis_presets = append(vorbis_presets, &Preset{
			Name: fmt.Sprintf("vorbis-v%d", quality),
			Config: &TranscodeConfig{
				Encoder:       "libvorbis",
				Container:     "ogg",
				FileExtension: "ogg",
				UseQuality:    true,
				Quality:       fmt.Sprintf("%d", quality),
			},
		})
	}

	add_to_presets("vorbis", vorbis_presets)
}

func add_g726_presets() {
	g726_presets := make([]*Preset, 0)

	g726_bitrates := []int{16, 24, 32, 40}

	for _, bitrate := range g726_bitrates {
		g726_presets = append(g726_presets, &Preset{
			Name: fmt.Sprintf("g726-%dk", bitrate),
			Config: &TranscodeConfig{
				Encoder:       "g726",
				Container:     "matroska",
				FileExtension: "mka",
				SampleRate:    "8000",
				Channels:      "1",
				UseBitrate:    true,
				Bitrate:       fmt.Sprintf("%dk", bitrate),
			},
		})
	}
	add_to_presets("g726", g726_presets)
}

func add_speex_presets() {
	speex_presets := make([]*Preset, 0)

	speex_qualities := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

	for _, quality := range speex_qualities {
		speex_presets = append(speex_presets, &Preset{
			Name: fmt.Sprintf("speex-q%d", quality),
			Config: &TranscodeConfig{
				Encoder:       "libspeex",
				Container:     "ogg",
				FileExtension: "ogg",
				UseQuality:    true,
				Quality:       fmt.Sprintf("%d", quality),
			},
		})
	}

	add_to_presets("speex", speex_presets)
}

func add_flac_preset() {
	add_to_presets("flac", []*Preset{
		{
			Name: "flac",
			Config: &TranscodeConfig{
				Encoder:       "flac",
				Container:     "flac",
				FileExtension: "flac",
			},
		},
	})
}

func add_wav_preset() {
	add_to_presets("wav", []*Preset{
		{
			Name: "wav",
			Config: &TranscodeConfig{
				Container:     "wav",
				FileExtension: "wav",
			},
		},
	})
}

func GetPresetByName(name string) (*Preset, error) {
	for _, category := range TranscodePresets {
		for _, preset := range category {
			if preset.Name == name {
				return preset, nil
			}
		}
	}
	return nil, fmt.Errorf("No preset with name %s", name)
}

func PrintTranscodePresets() {
	for cat_name, cat := range TranscodePresets {
		fmt.Printf("Category %s:\n", cat_name)
		for _, preset := range cat {
			fmt.Printf("- %s\n", preset.Name)
		}
	}
}

func init() {
	TranscodePresets = make(map[string][]*Preset, 0)

	add_mp3_presets()
	add_opus_presets()
	add_vorbis_presets()
	add_g726_presets()
	add_speex_presets()
	add_flac_preset()
	add_wav_preset()
}