"Expected 1 channels in audio block, got 2" when encoding a sample

[Niedzwiedzw]

so I'm working on this game installer (fallout 3 :)) and I need to resample ogg files.

https://github.com/Niedzwiedzw/hoolamike/blob/8c200bde1411f82e3b58f51008814a6f4c8ed82d/crates/hoola-audio/src/main.rs#L393

as you can see I'm using https://github.com/pdeljanov/Symphonia to decode the original audio and I'm trying to then push the samples into the writer.

here's a log from the application

2025-01-16T13:55:56.719845Z DEBUG hoola_audio: debug logging on
2025-01-16T13:55:56.719915Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}: symphonia_core::probe: found a possible format marker within [4f, 67, 67, 53, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 35, 2f] @ 0+2 bytes.
2025-01-16T13:55:56.719938Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}: symphonia_core::probe: found the format marker [4f, 67, 67, 53] @ 0+2 bytes.
2025-01-16T13:55:56.719961Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}: symphonia_format_ogg::page: grow page buffer to 8192 bytes
2025-01-16T13:55:56.719967Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}: symphonia_format_ogg::demuxer: starting new physical stream
2025-01-16T13:55:56.719973Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}: symphonia_format_ogg::demuxer: selected vorbis mapper for stream with serial=0x2f35
2025-01-16T13:55:56.720828Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}:new: hoola_audio: selected track [Track {
    id: 12085,
    codec_params: CodecParameters {
        codec: CodecType(
            4096,
        ),
        sample_rate: Some(
            44100,
        ),
        time_base: Some(
            TimeBase {
                numer: 1,
                denom: 44100,
            },
        ),
        n_frames: Some(
            3309248,
        ),
        start_ts: 0,
        sample_format: None,
        bits_per_sample: None,
        bits_per_coded_sample: None,
        channels: Some(
            FRONT_LEFT | FRONT_RIGHT,
        ),
        channel_layout: None,
        delay: None,
        padding: Some(
            81,
        ),
        max_frames_per_packet: None,
        packet_data_integrity: false,
        verification_check: None,
        frames_per_block: None,
        extra_data: Some(
            [
                1,
                118,
                111,
                114,
                98,
                105,
                115,
                0,
                0,
            ...]
2025-01-16T13:55:56.721910Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}:new: symphonia_codec_vorbis: vorbis: leftover bits in setup head extra data
2025-01-16T13:55:56.722002Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:from_file{path="/tmp/file_example_OOG_1MG.ogg"}:new: hoola_audio: return=Ok(FormatReaderIterator { selected_track: 12085 })
2025-01-16T13:55:56.722013Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}:next_packet{self=FormatReaderIterator { selected_track: 12085 }}:skip_metadata: hoola_audio: return=()
2025-01-16T13:55:56.722021Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}:next_packet{self=FormatReaderIterator { selected_track: 12085 }}: hoola_audio: next packet packet_dur=0 packet_ts=0 packet_track_id=12085
2025-01-16T13:55:56.722027Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}: hoola_audio: decoding packet
2025-01-16T13:55:56.722044Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}: hoola_audio: packet decode success spec=SignalSpec { rate: 44100, channels: FRONT_LEFT | FRONT_RIGHT }
2025-01-16T13:55:56.722057Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}: hoola_audio: copying decoded data into a buffer
2025-01-16T13:55:56.722063Z DEBUG running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:next{self=FormatReaderIterator { selected_track: 12085 }}: hoola_audio: return=Some(Ok(DecodedChunk { spec: SignalSpec { rate: 44100, channels: FRONT_LEFT | FRONT_RIGHT } }))
2025-01-16T13:55:56.722116Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:with_source_info{original_rate=44100 original_channel_count=2}:building_vobis_encoder: hoola_audio: target_frequency=48000
2025-01-16T13:55:56.722123Z  INFO running{command=ResampleOGG { context: FromTo { from: "/tmp/file_example_OOG_1MG.ogg", to: "/tmp/reencoded-ogg.ogg" }, target_frequency: 48000 }}:with_source_info{original_rate=44100 original_channel_count=2}:building_vobis_encoder: hoola_audio: target_channel_count=2
Error: resampling [from:?] -> ["/tmp/reencoded-ogg.ogg"]

Caused by:
    0: encoding sample
    1: Expected 1 channels in audio block, got 2

this happens when I run it with following parameters

RUST_LOG=debug cargo run --package hoola-audio --release -- resample-ogg /tmp/file_example_OOG_1MG.ogg  /tmp/reencoded-ogg.ogg --target-frequency 48000

I'm almost certain I'm misusing it so maybe someone could take a look at my code please?

[Niedzwiedzw]

all right, I've figured it out - I need to split channels into separate audio blocks

[Niedzwiedzw]

here's working code example for future reference https://github.com/Niedzwiedzw/hoolamike/blob/feature/tale-of-two-wastelands-installer/crates/hoola-audio/src/main.rs

[AlexTMjugador]

I'm happy to hear you've figured out a solution to your problem!

As you may have already noticed, vorbis_rs, like the C APIs it wraps and as stated in its documentation, expects audio sample blocks to be provided in planar format, which means the samples are structured as an array of arrays: the outer array represents the channels, and each inner array contains the consecutive samples for a channel.

For instance, [[a, b, c], [d, e, f]] would be a representation of a planar audio sample buffer for two channels, where the first channel would have samples [a, b, c], and the second channel samples [d, e, f].