[FFmpeg-devel] Stereo channel layout mapping
Michael Niedermayer
michaelni at gmx.at
Fri Aug 8 02:31:23 CEST 2014
On Thu, Aug 07, 2014 at 04:52:43PM +0200, Robert Krüger wrote:
> Hi,
>
> could someone explain, what the difference between those two is and
> when to use which one?
>
> #define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
> #define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
if you have a file with 2 channels these would likely be AV_CH_LAYOUT_STEREO
if you have a file with 5.1 that in addition have 2 channels for
stereo playback equipment then that would have 8 channels and use
AV_CH_LAYOUT_STEREO_DOWNMIX + whatever else for 5.1
>
> E.g. when I extract metadata and want to use that as a basis to
> display the channel info to a user in a UI it is a bit surprising to
> display "Front left" and "Front right" for the channels of a plain
> stereo file. I can handle that case manually but it would be nice to
> understand the rationale behind it.
>
> Regards,
>
> Robert
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>
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The bravest are surely those who have the clearest vision
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notwithstanding go out to meet it. -- Thucydides
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