Project announcement : New opensource AAC DirectShow filter, hosted on corecodec.org

[Atamido]

Good, looks like we're in agreement then. :)

[[Toff]]

I'm afraid that changing the volume level of the graph will not works correctly as the player is going to override this volume just after you load the file.
I was more thinking about something like : the decoder ask for the replaygain values to the filter he is connected to and apply the gain on the PCM data it output.

Originally posted by shitowax
I didn't find the time to code that yet, but this replay gain can be easily set from the splitter (before streaming, retrieve the volume interface of the graph and set it to the right level). And anyway, at least for .mp4 and .mov, it's contained in the file format, not in the audio bitstream, so, my opinion is that it's the business of the splitter to set that, not the audio decoder.

[shitowax]

The question is when precisely will the volume be set by the player ? I would say it's just after the graph has been built. If it's the case, then my method would work (cause I propose that the splitter set the volume when it start streaming). Of course if there is daemon in the player resetting the volume to the appropriate value all the time, then it's fucked up =).

Originally posted by [Toff]
I'm afraid that changing the volume level of the graph will not works correctly as the player is going to override this volume just after you load the file.
I was more thinking about something like : the decoder ask for the replaygain values to the filter he is connected to and apply the gain on the PCM data it output.

[Atamido]

I think that altering the PCM data directly so that the volume is always relative to whatever the user has set in the player is a better idea.

[ChristianHJW]

Originally posted by Pamel I think that altering the PCM data directly so that the volume is always relative to whatever the user has set in the player is a better idea.

I take it that most decoders will output 16 Bit Integer PCM ? If so, we could convert this to 32 Bit FP PCM in the replaygain filter, giving us a lot of headroom to adjust loudness during playback ? The standard DShow audio renderers should be able to handle this just fine ?

[[Toff]]

Changing the graph volume has another major drawback : you can only have a gain <= 1.0, in fact you can't amplify the sound, only reduce it.
And at the user interface level I'm not sure the user will understand why his volume slider is moving :D

Doing a replaygain standalone filter would be great but I'm not sure it's really possible to tell the filter when to load exactly, especially with all those audio filters (channel downmixer, audio switcher) around. You need to find the right MERIT.
Too bad because it would be the best solution as it will works for all codecs.

[bond]

perhaps valex can implement something like that in his matrix mixer?