What causes "invalid media timebase" in pion/webrtc?

Regenerate or fix the IVF file so the timebase numerator/denominator are non-zero (commonly 1/1000)

invalid media timebase

Error message

invalid media timebase

What it means

errInvalidMediaTimebase is returned when an IVF file header declares a zero timebase numerator or denominator. The timebase converts the header's timebase to presentation timestamps, so a zero value would cause division by zero and meaningless timestamps. The reader refuses to parse such files. It indicates a corrupt, truncated, or badly generated IVF file.

Solutions

Regenerate or fix the IVF file so the timebase numerator/denominator are non-zero (commonly 1/1000)
Validate header fields before feeding the stream to the reader
If you control the writing side, use ivfwriter to produce a spec-compliant header
Check that the file/buffer was fully populated before parsing (truncated writes)

Defensive patterns

Strategy: validation

Validate before calling

var h ivfreader.IVFFileHeader
// after parsing the header yourself or from ParseNextHeader result:
if h.TimebaseNumerator == 0 || h.TimebaseDenominator == 0 {
    return errors.New("ivf header has zero timebase")
}

Type guard

func hasValidTimebase(h *ivfreader.IVFFileHeader) bool {
    return h != nil && h.TimebaseNumerator != 0 && h.TimebaseDenominator != 0
}

Try / catch

r, h, err := ivfreader.NewWith(f)
if err != nil {
    if errors.Is(err, ivfreader.ErrInvalidMediaTimebase) { // or the package-exported sentinel
        return fmt.Errorf("corrupt IVF file: %w", err)
    }
    return err
}

Prevention

Validate IVF header fields before parsing packets
Generate IVF files with ivfwriter or a known-good muxer
Reject zeroed headers early when ingesting untrusted files
Check for truncated writes that leave header fields zero

When it happens

Trigger: Calling ivfreader.NewWith / ParseNextHeader on an IVF stream whose 32-byte header has TimebaseNumerator == 0 or TimebaseDenominator == 0.

Common situations: Files produced by a broken encoder, hand-crafted test fixtures with zeroed header fields, files truncated before the timebase fields were filled, or buffers not yet fully read when the header is parsed.

Related errors

AI-assisted analysis of pion/webrtc@8c25dc09fa (2026-09-03). Data as JSON: /api/errors/7134aa9ff4eb480f. Report an issue: GitHub.

Appendix: source

Thrown at pkg/media/ivfwriter/ivfwriter.go:24

import (
	"encoding/binary"
	"errors"
	"io"
	"os"

	"github.com/pion/rtp"
	"github.com/pion/rtp/codecs"
	"github.com/pion/rtp/codecs/av1/obu"
)

var (
	errFileNotOpened        = errors.New("file not opened")
	errInvalidNilPacket     = errors.New("invalid nil packet")
	errCodecUnset           = errors.New("codec is unset")
	errCodecAlreadySet      = errors.New("codec is already set")
	errNoSuchCodec          = errors.New("no codec for this MimeType")
	errInvalidMediaTimebase = errors.New("invalid media timebase")
)

type (
	codec int

	// IVFWriter is used to take RTP packets and write them to an IVF on disk.
	IVFWriter struct {
		ioWriter     io.Writer
		count        uint64
		seenKeyFrame bool

		codec codec

		timebaseDenominator uint32
		timebaseNumerator   uint32
		firstFrameTimestamp uint32
		clockRate           uint64
		videoWidth          uint16

View on GitHub (pinned to 8c25dc09fa)