Several FRAG_PARSING_ERROR errors emitted

[albertdaurell]

Is your feature request related to a problem? Please describe.

Hi all, a long time ago we detected a unique session that emitted several FRAG_PARSING_ERROR events for the same ts file.
While checking the code I found that this error is sent inside a loop

See src/demux/tsdemuxer.ts#L275:

for (let start = syncOffset; start < len; start += 188) {
  if (data[start] === 0x47) {
    ...
  } else {
    this.observer.emit(Events.ERROR, Events.ERROR, {
      type: ErrorTypes.MEDIA_ERROR,
      details: ErrorDetails.FRAG_PARSING_ERROR,
      fatal: false,
      reason: 'TS packet did not start with 0x47',
    });
  }
}

So, if there is an error while parsing the packet for sure other start offsets can have same issue.

Describe the solution you'd like

A possible solution ( see pull #4481 ) could be report only an error with the total of errors found, something like:

let tsPacketErrors = 0;
for (let start = syncOffset; start < len; start += 188) {
  if (data[start] === 0x47) {
    ...
  }
  else {
    tsPacketErrors++;
  }
}

if (tsPacketErrors > 0) {
  this.observer.emit(Events.ERROR, Events.ERROR, {
    type: ErrorTypes.MEDIA_ERROR,
    details: ErrorDetails.FRAG_PARSING_ERROR,
    fatal: false,
    reason: `Found ${tsPacketErrors} TS packet/s that did not start with 0x47`,
  });
}

Additional context

Pull created #4481