Merge pull request #354 from amiaopensource/weaver-branch

CDDA Emphasis

index.html

@@ -367,7 +367,7 @@
         <dt>-slicecrc 1</dt><dd>Adds CRC information for each slice. This makes it possible for a decoder to detect errors in the bitstream, rather than blindly decoding a broken slice. (Read more <a href="http://ndsr.nycdigital.org/diving-in-head-first/" target="_blank">here</a>).</dd>
         <dt>-slices 16</dt><dd>Each frame is split into 16 slices. 16 is a good trade-off between filesize and encoding time.</dd>
         <dt>-c:a copy</dt><dd>copies all mapped audio streams.</dd>
-        <dt><em>output_file</em>.mkv</dt><dd>path and name of the output file. Use the <code>.mkv</code> extension to save your file in a Matroska container. Optionally, choose a different extension if you want a different container, such as <code>.mov</code> or <code>.avi</code>.</dd>
+        <dt><em>output_file</em>.mkv</dt><dd>path and name of the output file. Use the <code>.mkv</code> extension to save your file in a Matroska container.</dd>
         <dt>-f framemd5</dt><dd>Decodes video with the framemd5 muxer in order to generate MD5 checksums for every frame of your input file. This allows you to verify losslessness when compared against the framemd5s of the output file.</dd>
         <dt>-an</dt><dd>ignores the audio stream when creating framemd5 (audio no)</dd>
         <dt><em>framemd5_output_file</em></dt><dd>path, name and extension of the framemd5 file.</dd>
@@ -883,6 +883,23 @@
     </div>
     <!-- ends RIAA equalization -->
 
+    <!-- CD De-emphasis -->
+    <label class="recipe" for="cd_eq">Reverse CD Pre-Emphasis</label>
+    <input type="checkbox" id="cd_eq">
+    <div class="hiding">
+      <h3>Reverse CD Pre-Emphasis</h3>
+      <p><code>ffmpeg -i <em>input_file</em> -af aemphasis=type=cd <em>output_file</em></code></p>
+      <p>This will apply de-emphasis to reverse the effects of CD pre-emphasis in the somewhat rare case of CDs that were created with this technology. Use this command to create more accurate listening copies of files that were ripped 'flat' (without any de-emphasis) where the original source utilized emphasis. For more information about CD pre-emphasis see the <a href="https://wiki.hydrogenaud.io/index.php?title=Pre-emphasis" target="_blank">Hydrogen Audio page</a> on this subject.</p>
+      <dl>
+        <dt>ffmpeg</dt><dd>starts the command</dd>
+        <dt><em>input_file</em></dt><dd>path, name and extension of the input file</dd>
+        <dt>-af aemphasis=type=cd</dt><dd>activates the aemphasis filter and sets it to use CD equalization</dd>
+        <dt><em>output_file</em></dt><dd>path and name of output file</dd>
+      </dl>
+      <p class="link"></p>
+    </div>
+    <!-- CD De-emphasis -->
+
     <!-- one pass loudnorm -->
     <label class="recipe" for="loudnorm_one_pass">One Pass Loudness Normalization</label>
     <input type="checkbox" id="loudnorm_one_pass">
@@ -1856,11 +1873,30 @@
         <dt>-c:a copy</dt><dd>ensures that FFmpeg will not transcode the audio to a different codec before generating the MD5 (by default FFmpeg will use 16 bit PCM for audio MD5s).</dd>
         <dt><em>output_file_2</em></dt><dd>is the output file for the audio stream MD5.</dd>
       </dl>
-      <p><strong>Note:</strong>The MD5s generated by running this command on WAV files are compatible with those embedded by the <a href="https://mediaarea.net/BWFMetaEdit" target="_blank">BWF MetaEdit</a> tool and can be compared.</p>
+      <p><strong>Note:</strong> The MD5s generated by running this command on WAV files are compatible with those embedded by the <a href="https://mediaarea.net/BWFMetaEdit" target="_blank">BWF MetaEdit</a> tool and can be compared.</p>
       <p class="link"></p>
     </div>
     <!-- ends Create stream md5s -->
 
+    <!-- Get checksum for video/audio stream -->
+    <label class="recipe" for="get_stream_checksum">Get checksum for video/audio stream</label>
+    <input type="checkbox" id="get_stream_checksum">
+    <div class="hiding">
+      <h3>Get checksum for video/audio stream</h3>
+      <p><code>ffmpeg -loglevel error -i <em>input_file</em> -map 0:v:0 -f hash -hash md5 -</code></p>
+      <p>This script will perform a fixity check on a specified audio or video stream of the file, useful for checking that the content within a video has not changed even if the container format has changed.</p>
+      <dl>
+        <dt>ffmpeg</dt><dd>starts the command</dd>
+        <dt>-loglevel error</dt><dd>sets the verbosity of logging to show all errors</dd>
+        <dt>-i <em>input_file</em></dt><dd>path, name and extension of the input file</dd>
+        <dt>-map 0:v:0</dt><dd>designated the first video stream as the stream on which to perform this hash generation operation. <code>-map 0</code> can be used to run the operation on all streams.</dd>
+        <dt>-f hash -hash md5</dt><dd>produce a checksum hash, and set the hash algorithm to md5. See the official <a href="https://ffmpeg.org/ffmpeg-formats.html#hash">documentation on hash</a> for other algorithms.</dd>
+        <dt>-</dt><dd>FFmpeg syntax requires a specified output, and <code>-</code> is just a place holder. No file is actually created.</dd>
+      </dl>
+      <p class="link"></p>
+    </div>
+    <!-- ends Get checksum for video/audio stream -->
+
     <!-- QCTools Report -->
     <label class="recipe" for="qctools">QCTools report (with audio)</label>
     <input type="checkbox" id="qctools">
@@ -2460,6 +2496,20 @@
         <p class="link"></p>
       </div>
       <!-- ends Rip with CDDA2WAV -->
+
+      <!-- Check for CD Emphasis -->
+        <label class="recipe" for="cd-emph-check">Check/Compensate for CD Emphasis</label>
+        <input type="checkbox" id="cd-emph-check">
+        <div class="hiding">
+          <h3>Check/Compensate for CD Emphasis</h3>
+          <p>While somewhat rare, certain CDs had 'emphasis' applied as a form of noise reduction. This seems to mostly affect early (1980s) era CDs and some CDs pressed in Japan. Emphasis is part of the <a href="https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio#Standard">Red Book standard</a> and, if present, must be compensated for to ensure accurate playback. CDs that use emphasis contain flags on tracks that tell the CD player to de-emphasize the audio on playback. When ripping a CD with emphasis, it is important to take this into account and either apply de-emphasis while ripping, or if storing a 'flat' copy, create another de-emphasized listening copy.</p>
+          <p>The following commands will output information about the presence of emphasis when run on a target CD:</p>
+          <p><strong>Cdda2wav:</strong> <code>cdda2wav -J</code></p>
+          <p><strong>CD Paranoia:</strong> <code>cdparanoia -Q</code></p>
+          <p>In order to compensate for emphasis during ripping while using Cdda2wav, the <code>-T</code> flag can be added to the <a href="#cdda2wav">standard ripping command</a>. For a recipe to compensate for a flat rip, see the section on <a href="#cd_eq">de-emphasizing with FFmpeg</a>.
+          <p class="link"></p>
+        </div>
+      <!-- Check for CD Emphasis -->
     </div>
     <!-- ends CDDA Tools -->