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<p>Hi,</p>
<p>I don't know the details, but might be the one to blame: sounds
like an artifact of being able to switch between RC (range coder)
and rANS during development (I think Alex Converse was
responsible), while finally RC was used.<br>
</p>
<p>Only rANS requires buffer for backward encoding (is necessarily
LIFO), while RC can be made both LIFO or FIFO.</p>
<p>Maybe they have left LIFO for this compatibility (?) - if it goes
deeper it might need some larger rewriting ...<br>
</p>
<p>Best,</p>
<p>Jarek Duda</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">W dniu 27.07.2020 o 11:07, Knight Kim
pisze:<br>
</div>
<blockquote type="cite"
cite="mid:CA+o+War4r6Yc3GcTZZT4PXUdeMT1i5ycRCGZv2vOcRL29SpWfA@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">Hello,
<div><br>
</div>
<div>I am implementing entropy HW for AV1 video codec.</div>
<div>I want to make the HW with the smallest precarry buffer.</div>
<div>Currently, aom encoder is scanning reverse direction adding
precarry to previous buffer point.</div>
<div>It means that I should keep all bitstreams in a tile, and
scan all the bitstreams then generate it.</div>
<div>At HW point of view, this kind of operation is quite
inefficient.</div>
<div>Is there any way to implement the entropy encoder without
precarry back-propagation?</div>
<div>Can I determine the maximum length of back-propagation?<br>
</div>
<div><br>
</div>
<div>Thanks.</div>
</div>
<br>
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<pre class="moz-signature" cols="72">--
dr Jarosław Duda
Institute of Computer Science and Computer Mathematics,
Jagiellonian University, Cracow, Poland
<a class="moz-txt-link-freetext" href="http://th.if.uj.edu.pl/~dudaj/">http://th.if.uj.edu.pl/~dudaj/</a></pre>
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