invalid-third-block.html

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<!DOCTYPE html>

<html>

<head>

<meta charset=utf-8>

<title>Unknown Track Number in Third Block</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="mediasource-util.js"></script>

</head>

<body>

</body>

<script>

// Test that an unknown track number in the third webm block triggers the

// append error algorithm.

// https://w3c.github.io/media-source/#byte-stream-formats

// The user agent MUST run the append error algorithm when any combination of

// an initialization segment and any contiguous sequence of media segments

// satisfies the following conditions:

// 1. The number and type (audio, video, text, etc.) of all tracks in the

//    media segments are not identified.

promise_test(async t => {

  const audio = document.createElement('audio');

  audio.controls = true;

  audio.watcher = new EventWatcher(t, audio, ['error']);

  document.body.appendChild(audio);

  const source = new MediaSource();

  source.watcher = new EventWatcher(t, source, ['sourceopen']);

  audio.src = URL.createObjectURL(source);

  await source.watcher.wait_for('sourceopen');

  const resource = await MediaSourceUtil.fetchResourceOfManifest(

    t, 'webm/test-a-128k-44100Hz-1ch-manifest.json');

  assert_implements_optional(MediaSource.isTypeSupported(resource.type),

                             `${resource.type} supported`);

  const buffer = source.addSourceBuffer(resource.type);

  buffer.watcher = new EventWatcher(t, buffer, ['error', 'updateend']);

  // Intentionally append data ending at the end of a cluster having an

  // invalid track number in a block that is after the second block in the

  // cluster, because Gecko had a bug that failed to detect some demux errors

  // in this situation.

  resource.data = resource.data.subarray(0, resource.cluster_start[1]);

  // Choose a track number of zero, which is not in the init segment.

  const track_number = 0;

  // Set the high bit of an octet, for a single-octet EBML VINT.

  const track_number_vint = 1 << 7 | track_number;

  // Skip two bytes for the EBML element ID and data size, and overwrite the

  // track number.

  resource.data[Number(resource.block_start[2]) + 2] = track_number_vint;

  buffer.appendBuffer(resource.data);

  await Promise.all([

    buffer.watcher.wait_for(['error', 'updateend']),

    audio.watcher.wait_for('error'),

]);

}, 'invalid-third-block');

</script>

</html>