[pulseaudio-discuss] bitstream hd formats over hdmi?

Alexander E. Patrakov patrakov at gmail.com
Fri Feb 13 07:21:53 PST 2015

13.02.2015 20:05, Andrew Henry wrote:
> I was always under the impression that it is better to let the AV
> receiver decode the bitstream, rather than supplying the receiver with
> an already decoded (L)PCM signal, but your comment made me think a bit
> about this.  What is the reasoning behind letting, for example ffmpeg do
> the decoding in software, then just passing a 7.1 PCM signal over hdmi
> to AV receiver?  Do you think ffmpeg would do a better job than a
> receiver?  Does the receiver handle a digital birstream in a different
> way to what it would handle a PCM signal?

Yes, there is some difference. The dialog normalization feature is 
available only on compressed streams and not on PCM, because the dialog 
level information is explicitly encoded in the compressed formats. But - 
this feature is also implemented in the ffmpeg decoder, so you can 
adjust the dialog level from your player application, if it exposes this 

But in my opinion - it's just a question of additional infrastructure 
complexity only for the marketing hype that exists for compressed formats.

Alexander E. Patrakov

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