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Subject: Re: Opus codec developments

Re: Opus codec developments

From: RafaŽl Carrť <funman_at_videolan.org>
Date: Fri, 27 Jul 2012 18:00:41 +0200

Le 2012-07-27 15:32, Magnus Holmgren a ťcrit :
> On 2012-07-27 15:24, Bertrik Sikken wrote:
>
>>>> * Applying global gain from the opus audio file is not implemented
>>>> (not sure if replaygain is working)
>>>
>>> Fixed (it's part of the codec, not related to replaygain although we
>>> might want to implement replaygain for e.g. vorbis too).
>>
>> Thanks.
>>
>> (Replaygain for vorbis/upus doesn't look that complicated really, BTW).
>
> A call to codec_set_replaygain() when starting a new track should be enough. It
> looks like the existing tag parsing code is used; if so Replaygain tags are
> already handled.

I think the tags are not read at all from the file:

http://git.videolan.org/?p=vlc.git;a=blob;f=modules/codec/vorbis.c;h=f833f1c10e4e7e1f8b87ac10bade4f23f92db9e0;hb=HEAD#l558

git grep \"REPLAYGAIN shows no result

>
> By the way, how is resampling handled? From what I've read, Opus always uses 48
> kHz internally, so what resampler is used? The one in Opus or the one in Rockbox?

in lib/rbcodec/codecs/opus.c:

sample_rate = 48000;
...
opus_decoder_init(st, sample_rate, header.channels);
...
ci->configure(DSP_SET_FREQUENCY, sample_rate);

So it seems rockbox asks for 48kHz and then resamples it itself, we
could compare both maybe.

Did someone run test_codec yet? saratoga?
Received on 2012-07-27


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