SubtitleEdit/subtitleedit · error · InvalidDataException

Cannot read bits per sample of {Header.BitsPerSample}

Error message

Cannot read bits per sample of {Header.BitsPerSample}

What it means

Thrown by GetSampleDataReader when Header.BytesPerSample (derived from BitsPerSample, rounded up to whole bytes) is not 1, 2, 3, or 4. The reader only has implementations for 8/16/24/32-bit PCM samples; any other byte-per-sample value (e.g. 0 from a 0-bit header, or a non-PCM format) has no read path. The message echoes BitsPerSample rather than BytesPerSample, which can be slightly misleading.

Source

Thrown at src/ui/Logic/Media/WaveToVisualizer2.cs:914

    private double GetSampleAndChannelScale()
    {
        return GetSampleScale() / Header.NumberOfChannels;
    }

    private ReadSampleDataValue GetSampleDataReader()
    {
        switch (Header.BytesPerSample)
        {
            case 1:
                return ReadValue8Bit;
            case 2:
                return ReadValue16Bit;
            case 3:
                return ReadValue24Bit;
            case 4:
                return ReadValue32Bit;
            default:
                throw new InvalidDataException("Cannot read bits per sample of " + Header.BitsPerSample);
        }
    }

    private WriteSampleDataValue GetSampleDataWriter()
    {
        switch (Header.BytesPerSample)
        {
            case 1:
                return WriteValue8Bit;
            case 2:
                return WriteValue16Bit;
            case 3:
                return WriteValue24Bit;
            case 4:
                return WriteValue32Bit;
            default:
                throw new InvalidDataException("Cannot write bits per sample of " + Header.BitsPerSample);
        }

View on GitHub (pinned to 17a9f07487)

Solutions

1. Check Header.BitsPerSample is 8, 16, 24, or 32 before invoking sample-reading APIs.
2. For 32-bit float audio, convert to 16-bit PCM first or extend the reader.
3. Validate Header.AudioFormat == PCM (1) before reading samples.
4. Re-encode the source WAV to a supported PCM bit depth if it is an exotic format.

Example fix

// before
var reader = GetSampleDataReader();

// after
if (Header.BytesPerSample is not (1 or 2 or 3 or 4))
    throw new NotSupportedException($"Unsupported bit depth: {Header.BitsPerSample}-bit");
var reader = GetSampleDataReader();

if (wave.Header.BytesPerSample is not (1 or 2 or 3 or 4))
    throw new NotSupportedException($"Unsupported bit depth: {wave.Header.BitsPerSample}-bit (AudioFormat={wave.Header.AudioFormat})");
if (wave.Header.AudioFormat != WaveHeader2.AudioFormatPcm && wave.Header.AudioFormat != 0xFFFE)
    throw new NotSupportedException("Only PCM WAV is supported for sample reading");

static bool IsSupportedReadBitDepth(WaveHeader2 h) => h.BytesPerSample is 1 or 2 or 3 or 4;

try { var reader = GetSampleDataReader(); }
catch (InvalidDataException ex) when (ex.Message.Contains("Cannot read")) { /* convert to 16-bit PCM */ }

When it happens

Trigger: Calling any sample-reading API (GeneratePeaks, GenerateSpectrogram, GetSamples) on a WAV whose BitsPerSample is 0, 12, an unusual value, or whose AudioFormat is non-PCM (float/compressed) so BitsPerSample does not map to 8/16/24/32.

Common situations: Opening a 32-bit float WAV (AudioFormat 3) where BitsPerSample is 32 but the value semantics differ; a corrupt fmt chunk yielding BitsPerSample 0; a 20-bit file that rounds up but is otherwise mishandled; header corruption.

Related errors

• Cannot write bits per sample of {Header.BitsPerSample}
• Peaks file must be 16 bits per sample.
• Stream is too small
• Peaks file must have 1 or 2 channels.
• Too many bytes for CCData!

AI-assisted analysis of SubtitleEdit/subtitleedit@17a9f07487 (2026-08-13). Data as JSON: /api/errors/dbdf8af9f8bf1621. Report an issue: GitHub.