5.1 audio gets downmixed to stereo using default settings without any warning.
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Description

Reported: https://bugs.kde.org/show_bug.cgi?id=361970

I'm using kdenlive 15.12.3-1 on debian testing.
I've got a recording with ac3 Audio and 5.1(side) channel layout. I can see that kdenlive recognizes the 6 audio channels after enabling Timeline->Thumbnails->Separate channels in the settings. But when I render the project (e.g. with the H.264/AAC fast profile) the audio is downmixed to stereo.

Reproducible: Always

Steps to Reproduce:

  1. Open video with 5.1(side) audio
  2. Render the project with the H.264/AAC fast profile
  3. Examine the audio channel layout of the rendered file, e.g. with ffmpeg

    Actual Results: The rendered file has got stereo audio.

    Expected Results: The rendered file should have 5.1(side) audio, i.e. the same channel layout as the source files.

A user suggests adding a parameter fixes this:

I managed to get 6ch audio by modifying the render parameters to include: channels=6 and for AC3 audio add acodec=ac3

As an example I modified the H.264/AAC high profile:

properties=x264-medium g=120 crf=%quality acodec=ac3 ab=%audiobitrate+'k' channels=6

The task would be to add a UI in the render panel to downmix or maintain the current channel layout? Of course Kdenlive would have to automatically suggest the correct channel layout parameters.

afarid created this task.Oct 14 2018, 1:37 PM