package opus // https://tools.ietf.org/html/rfc7845 import ( "bytes" "github.com/wader/fq/format" "github.com/wader/fq/format/registry" "github.com/wader/fq/pkg/decode" ) var vorbisComment []*decode.Format func init() { registry.MustRegister(&decode.Format{ Name: format.OPUS_PACKET, Description: "Opus packet", DecodeFn: opusDecode, Dependencies: []decode.Dependency{ {Names: []string{format.VORBIS_COMMENT}, Formats: &vorbisComment}, }, }) } func opusDecode(d *decode.D, in interface{}) interface{} { var prefix []byte if d.BitsLeft() >= 8*8 { prefix = d.PeekBytes(8) } switch { case bytes.Equal(prefix, []byte("OpusHead")): d.FieldValueStr("type", "head", "") d.FieldUTF8("prefix", 8) d.FieldU8("version") channelCount := d.FieldU8("channel_count") d.FieldU16("pre_skip") d.FieldU32LE("sample_rate") d.FieldU16LE("output_gain") mapFamily := d.FieldU8("map_family") if mapFamily != 0 { d.FieldU8("stream_count") d.FieldU8("coupled_count") i := uint64(0) d.FieldArrayLoopFn("channel_mappings", func() bool { return i < channelCount }, func(d *decode.D) { d.FieldU8("channel_mapping") }) } case bytes.Equal(prefix, []byte("OpusTags")): d.FieldValueStr("type", "tags", "") d.FieldUTF8("prefix", 8) d.FieldFormat("comment", vorbisComment, nil) default: d.FieldValueStr("type", "audio", "") d.FieldStructFn("toc", func(d *decode.D) { d.FieldStructFn("config", func(d *decode.D) { configurations := map[uint64]struct { mode string bandwidth string frameSize float64 }{ 0: {"SILK-only", "NB", 10}, 1: {"SILK-only", "NB", 20}, 2: {"SILK-only", "NB", 40}, 3: {"SILK-only", "NB", 60}, 4: {"SILK-only", "MB", 10}, 5: {"SILK-only", "MB", 20}, 6: {"SILK-only", "MB", 40}, 7: {"SILK-only", "MB", 60}, 8: {"SILK-only", "WB", 10}, 9: {"SILK-only", "WB", 20}, 10: {"SILK-only", "WB", 40}, 11: {"SILK-only", "WB", 60}, 12: {"Hybrid", "SWB", 10}, 13: {"Hybrid", "SWB", 20}, 14: {"Hybrid", "FB", 10}, 15: {"Hybrid", "FB", 20}, 16: {"CELT-only", "NB", 2.5}, 17: {"CELT-only", "NB", 5}, 18: {"CELT-only", "NB", 10}, 19: {"CELT-only", "NB", 20}, 20: {"CELT-only", "WB", 2.5}, 21: {"CELT-only", "WB", 5}, 22: {"CELT-only", "WB", 10}, 23: {"CELT-only", "WB", 20}, 24: {"CELT-only", "SWB", 2.5}, 25: {"CELT-only", "SWB", 5}, 26: {"CELT-only", "SWB", 10}, 27: {"CELT-only", "SWB", 20}, 28: {"CELT-only", "FB", 2.5}, 29: {"CELT-only", "FB", 5}, 30: {"CELT-only", "FB", 10}, 31: {"CELT-only", "FB", 20}, } n := d.FieldU5("config") config := configurations[n] d.FieldValueStr("mode", config.mode, "") d.FieldValueStr("bandwidth", config.bandwidth, "") d.FieldValueFloat("frame_size", config.frameSize, "") }) d.FieldBool("stereo") d.FieldStructFn("frames_per_packet", func(d *decode.D) { framesPerPacketConfigs := map[uint64]struct { frames uint64 mode string }{ 0: {1, "1 frame"}, 1: {2, "2 frames, equal size"}, 2: {2, "2 frames, different size"}, 3: {0, "arbitrary number of frames"}, } n := d.FieldU2("config") config := framesPerPacketConfigs[n] d.FieldValueU("frames", config.frames, "") d.FieldValueStr("mode", config.mode, "") }) d.FieldBitBufLen("data", d.BitsLeft()) }) } return nil }