<html>
<head>
<base href="https://bugs.webkit.org/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [GStreamer][MSE] Actually implement flush() on playback pipeline"
href="https://bugs.webkit.org/show_bug.cgi?id=169202">169202</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[GStreamer][MSE] Actually implement flush() on playback pipeline
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>Product</th>
<td>WebKit
</td>
</tr>
<tr>
<th>Version</th>
<td>WebKit Local Build
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Unspecified
</td>
</tr>
<tr>
<th>OS</th>
<td>Unspecified
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>Normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P2
</td>
</tr>
<tr>
<th>Component</th>
<td>Media Elements
</td>
</tr>
<tr>
<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>eocanha@igalia.com
</td>
</tr></table>
<p>
<div>
<pre>The GStreamer MSE implementation didn't implement flush() because GStreamer didn't offer a natural way to flush just one (audio/video) stream instead of flushing the whole pipeline. As this use case was only relevant during seeks, we just did nothing and waited the seek to happen and perform the flush by itself (a seek implies a flush in GStreamer).
However, we have recently detected that flush() also happens in YouTube TV when a quality change happens, so the web page reenqueues higher quality samples and overwrites some buffered ranges having lower quality and having already been enqueued for playback. In that case, flush() should clean the already enqueued data only on that stream and a new reenqueue would provide more accurate (higher resolution) data. As flush() does nothing in our case, the outcome was that the user could see some parts of the video "played twice", together with some audio/video desynchronization.
The right fix would be to properly implement per-stream flushing.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the assignee for the bug.</li>
</ul>
</body>
</html>