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<p>Raised as <a moz-do-not-send="true"
href="https://code.mythtv.org/trac/ticket/13629#ticket">https://code.mythtv.org/trac/ticket/13629#ticket</a><br>
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-------- Forwarded Message --------
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Subject:
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<td>V31 software playback Double rate de-interlacer causing
audio to go out of step</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date: </th>
<td>Tue, 2 Jun 2020 16:25:57 +0100</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">From: </th>
<td>John <a class="moz-txt-link-rfc2396E" href="mailto:jksjdevelop@gmail.com"><jksjdevelop@gmail.com></a></td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">To: </th>
<td>Discussion about MythTV <a class="moz-txt-link-rfc2396E" href="mailto:mythtv-users@mythtv.org"><mythtv-users@mythtv.org></a></td>
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<br>
<br>
There have been a few mentions here that the double rate
de-interlacer can cause large shifts in audio and juddery playback
when using ffmpeg for playback.<br>
<br>
Platform Intel Ubuntu<br>
<br>
The issue does not occur with VDPAU NVDEC or VAAPI.<br>
<br>
This issue was not present in early versions of V31.<br>
<br>
I tried to bisect it today but not being a developer may have got
it wrong , the bisect however did land on a likely candidate.<br>
<br>
commit 31c68a14e816df1ff256280821aeaf8e5f14610d (refs/bisect/bad)<br>
Author: Mark Kendall <a class="moz-txt-link-rfc2396E" href="mailto:mark.kendall@gmail.com"><mark.kendall@gmail.com></a><br>
Date: Tue Mar 10 20:50:03 2020 +0000<br>
<br>
MythDeinterlacer: Don't cleanup deinterlacer if already
deinterlaced<br>
<br>
(cherry picked from commit
62a8f70bcb6aa1015f545808e3b9007666b6dbb8)<br>
<br>
--a quote from another website explaining the dynamics.<br>
<br>
The problem occurs with UK DVB-T2 streams which use on-the-fly
dynamic progressive / interlaced encoder switching.<br>
These channels dynamically switch the broadcast encoders between
1080p25 and 1080i25 (i.e. actually switch the encoder from
progressive to interlaced) on a GOP-by-GOP basis, rather than just
staying permanently in 1080i25 (and using MBAFF to handle
static/native progressive content).<br>
<br>
I have tried before to raise a fault report but never managed to
log in.<br>
<br>
If I do a git checkout fixes/31 to go forward to current head how
do I just eliminate that single change?<br>
<br>
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