Answers.Body: <p>No need to use pan filter, you can reassign channel layout using the channelmap filter.</p>
  
  <pre><code>ffmpeg -i ticket1474.mov -af channelmap=0 -b:a 128k -map 0:v -map 0:a -y sample.mp4
  </code></pre>
  
  <p>See <a href="http://ffmpeg.org/ffmpeg-filters.html#channelmap" rel="nofollow noreferrer">docs</a> for channelmap filter.</p>
  
  <p>I've skipped mapping the timecode track. ffmpeg will set it as metadata in the input file, and the MP4 muxer will pick it up from there.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-08-29T09:22:59.517Z
Answers.LastActivityDate: 2019-08-29T09:22:59.517Z
Answers.UserDisplayName: Gyan
Body: <h2>Problem</h2>
  
  <p>I want to convert the MOV file containing the separated FL/FR audio streams to MP4 file, transcoding the video to h264 and the audio to AAC.
  However, it fails with the following error:</p>
  
  <p><code>[aac @ 0x7ff515000c00] Unsupported channel layout "1 channels (FL)"</code></p>
  
  <p>The source video and command what I used is as the following section.</p>
  
  <h2>How To Reproduce</h2>
  
  <p>Download <code>ticket1474.mov</code> as the source from <a href="https://trac.ffmpeg.org/ticket/1474" rel="nofollow noreferrer">https://trac.ffmpeg.org/ticket/1474</a>, 
  this source contains the following streams:
  (The streams in issue are #0:1 and #0:2)</p>
  
  <pre><code>    Stream #0:0(eng): Video: mpeg2video (Main) (xdvf / 0x66766478), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 34801 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 59.94 tbc (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Video Media Handler
        encoder         : XDCAM EX 1080p30 (35 Mb/s VBR)
        timecode        : 00:00:00;00
      Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FL), s16, 768 kb/s (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Sound Media Handler
      Stream #0:2(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FR), s16, 768 kb/s (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Sound Media Handler
      Stream #0:3(eng): Data: none (tmcd / 0x64636D74)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Time Code Media Handler
        reel_name       : Untitled
        timecode        : 00:00:00;00
  </code></pre>
  
  <p>Then run the following command:</p>
  
  <pre><code>$ ffmpeg -i ticket1474.mov -b:a 128k -map 0 -y sample.mp4
  </code></pre>
  
  <p>You'll get the following error:</p>
  
  <pre><code>(snip)
  
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (mpeg2video (native) -&gt; h264 (libx264))
    Stream #0:1 -&gt; #0:1 (pcm_s16le (native) -&gt; aac (native))
    Stream #0:2 -&gt; #0:2 (pcm_s16le (native) -&gt; aac (native))
    Stream #0:3 -&gt; #0:3 (copy)
  
  (snip)
  
  [aac @ 0x7ffbd203e400] Unsupported channel layout "1 channels (FL)"
  Error initializing output stream 0:1 -- Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height
  Conversion failed!
  </code></pre>
  
  <h2>ffmpeg Version</h2>
  
  <pre><code>$ ffmpeg -v
  ffmpeg version N-93875-gc2771bbf81-tessus 
  </code></pre>
  
  <p>Note: Stable version (ffmpeg-4.2) also fails.</p>
  
  <h2>What I Tried (Converting FL/FR streams to dual mono channel)</h2>
  
  <p>I guessed the problem can be solved if I could convert FL/FR streams to dual mono streams.</p>
  
  <p>But I couldn't find the appropriate usage of ffmpeg for such scene.</p>
  
  <p>The command I have tried is the following which also failed: </p>
  
  <pre><code>$ ffmpeg -i ticket1474.mov -b:a 128k -filter_complex '[0:1]pan=mono|FC=FL[mono];[0:2]pan=mono|FC=FR[mono]' -y sample.mp4
  
  (snip)
  
  Filter pan has an unconnected output
  </code></pre>
  
  <p>Any ideas?</p>
  
Tags: <ffmpeg><audio>
Title: ffmpeg: How to fix `Unsupported channel layout "1 channels (FL)" error`, when I convert the source containing separated FL/FR audio streams?
UserDisplayName: kaorukobo
ThreadText: # ffmpeg: How to fix `Unsupported channel layout "1 channels (FL)" error`, when I convert the source containing separated FL/FR audio streams?
  
  (Asked by: username_0 on 2019-08-29)
  
  ## Problem
  
  I want to convert the MOV file containing the separated FL/FR audio streams to MP4 file, transcoding the video to h264 and the audio to AAC.
  However, it fails with the following error:
  
  `[aac @ 0x7ff515000c00] Unsupported channel layout "1 channels (FL)"`
  
  The source video and command what I used is as the following section.
  
  ## How To Reproduce
  
  Download `ticket1474.mov` as the source from <https://trac.ffmpeg.org/ticket/1474>,
  this source contains the following streams:
  (The streams in issue are #0:1 and #0:2)
  
  ```
      Stream #0:0(eng): Video: mpeg2video (Main) (xdvf / 0x66766478), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 34801 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 59.94 tbc (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Video Media Handler
        encoder         : XDCAM EX 1080p30 (35 Mb/s VBR)
        timecode        : 00:00:00;00
      Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FL), s16, 768 kb/s (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Sound Media Handler
      Stream #0:2(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FR), s16, 768 kb/s (default)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Apple Sound Media Handler
      Stream #0:3(eng): Data: none (tmcd / 0x64636D74)
      Metadata:
        creation_time   : 2012-06-19T21:18:43.000000Z
        handler_name    : Time Code Media Handler
        reel_name       : Untitled
        timecode        : 00:00:00;00
  
  ```
  
  Then run the following command:
  
  ```
  $ ffmpeg -i ticket1474.mov -b:a 128k -map 0 -y sample.mp4
  
  ```
  
  You'll get the following error:
  
  ```
  (snip)
  
  Stream mapping:
    Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))
    Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
    Stream #0:2 -> #0:2 (pcm_s16le (native) -> aac (native))
    Stream #0:3 -> #0:3 (copy)
  
  (snip)
  
  [aac @ 0x7ffbd203e400] Unsupported channel layout "1 channels (FL)"
  Error initializing output stream 0:1 -- Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height
  Conversion failed!
  
  ```
  
  ## ffmpeg Version
  
  ```
  $ ffmpeg -v
  ffmpeg version N-93875-gc2771bbf81-tessus 
  
  ```
  
  Note: Stable version (ffmpeg-4.2) also fails.
  
  ## What I Tried (Converting FL/FR streams to dual mono channel)
  
  I guessed the problem can be solved if I could convert FL/FR streams to dual mono streams.
  
  But I couldn't find the appropriate usage of ffmpeg for such scene.
  
  The command I have tried is the following which also failed:
  
  ```
  $ ffmpeg -i ticket1474.mov -b:a 128k -filter_complex '[0:1]pan=mono|FC=FL[mono];[0:2]pan=mono|FC=FR[mono]' -y sample.mp4
  
  (snip)
  
  Filter pan has an unconnected output
  
  ```
  
  Any ideas?
  
  **Tags:** ffmpeg, audio
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-08-29. Score: 3 | Accepted answer
  
  No need to use pan filter, you can reassign channel layout using the channelmap filter.
  
  ```
  ffmpeg -i ticket1474.mov -af channelmap=0 -b:a 128k -map 0:v -map 0:a -y sample.mp4
  
  ```
  
  See [docs](http://ffmpeg.org/ffmpeg-filters.html#channelmap) for channelmap filter.
  
  I've skipped mapping the timecode track. ffmpeg will set it as metadata in the input file, and the MP4 muxer will pick it up from there.
  
  
  ---
  
  