<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal">ffmpeg Team,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">According to the ffmpeg documentation the AC-3 encoder has options to access all Dolby metadata per the Dolby Metadata Guide link available on ffmpeg.org. This is true for all Dolby metadata except the Dynamic Range Compression (DRC) profile
selection. We are experiencing volume discrepancies from set top boxes while playing content encoded from ffmpeg. We also use Minnetonka’s Surcode for Dolby Digital 5.1 AC-3 encoding software. It does allow the selection of a DRC profile and there are no audio
discrepancies as seen with ffmpeg. Is this an option that can be added or can someone offer a solution to this issue?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Command lines used:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">First pass – ouput is parsed as $loudnorm variable with properties:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">ffmpeg.exe -i input.wav -vn -af "loudnorm=print_format=summary" -f null –
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Second pass:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">ffmpeg.exe -i input.wav -vn -c:a ac3 -ac 2 -b:a 192k -ar 48000 -af "loudnorm=I=-24:offset=$($loudnorm.Target_Offset_LU):linear=true:measured_I=$($loudnorm.Input_Integrated_LUFS):measured_TP=$($loudnorm.Input_True_Peak_dbTP):measured_LRA=$($loudnorm.Input_LRA_LU):measured_thresh=$($loudnorm.Input_Threshold_LUFS)"
-dsur_mode 0 -dialnorm -24 -y output.ac3<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">At a later step this AC-3 is multiplexed into a MPEG2TS stream.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The output file created has a dialnorm stamp of -24 and is read at -24 LUFS with the Dolby Digital Meter utility and ffmpeg’s loudnorm audio filter. So all appears acceptable, but the AC-3 consistently plays back at a lower volume level
from the STB.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any assistance would be appreciated. Thank you.<o:p></o:p></p>
</div>
The contents of this e-mail message and <br>any attachments are intended solely for the <br>addressee(s) and may contain confidential <br>and/or legally privileged information. If you<br>are not the intended recipient of this message<br>or if this message has been addressed to you <br>in error, please immediately alert the sender<br>by reply e-mail and then delete this message <br>and any attachments. If you are not the <br>intended recipient, you are notified that <br>any use, dissemination, distribution, copying,<br>or storage of this message or any attachment <br>is strictly prohibited.</body>
</html>