ChristianHJW
9th January 2003, 14:21
Hi,
just out of curiosity, despite not allowing VBR audio, what are the actual limitations of the ACM format here ?
Would it allow to make things like
- sampling rate conversion
- one pass normalizing of PCM WAV
- muxing of external AC3 files into AVI via ACM
I dont say it should be done, all i would like to investigate is if it was possible at all ? DG had similar plans with a DirectShow filter IIRC, but unfortunately there is no good encoding tool based on Dshow as of yet, and the future of Vdub 2 is pretty uncertain here ( Avery made some comments about Dshow in this respect recently ).
Main questions i'd love to see answered :
1. Sampling rate conversion : If any video encoding tool is calling an ACM audio codec ( like Fraunhofer MP3 ) for a specific sampling rate of the existing audio stream ( say 44100 Hz ) it will only show the list of those available that can handle this sampling rate on their input. Now, for a 44.1 Khz rate it will also show those that will output to a 22.05 Khz sampling rate, correct ? This is an indication to me that ACM does allow to have different sampling rates on input and output, but what about things like a 48 KHz to 44,1 KHz conversion, done with a BeSweet.ACM using SSRC in 32 bit FP mode, or even a SSRC.ACM ? Is the ACM codec allowed to write any value in the tag indicating sampling rate, or is this limited somehow ?
2. One pass normalizing : Using ReplayGain or MP3 gain it was maybe possible to perform one pass normalizing somehow ? No idea how its done though, i never understood replaygain good enough.
Think about capturing in Vdub guys !! Wouldnt it be great to have sound normalized on capturing automatically, when outputting to PCM WAV or MP3 ? How could we write the tag if capturing is finished ?
3. Muxing external audio files like AC3 or DTS into AVI from a BeSweet.ACM codec : The source file could be set in the configuration dialogue box somehow, and there you go muxing in any video editing application that can handle ACM codecs ...
I guess i am just dreaming here ... just look at it like a funny kind of brainstorming folks :D ....
just out of curiosity, despite not allowing VBR audio, what are the actual limitations of the ACM format here ?
Would it allow to make things like
- sampling rate conversion
- one pass normalizing of PCM WAV
- muxing of external AC3 files into AVI via ACM
I dont say it should be done, all i would like to investigate is if it was possible at all ? DG had similar plans with a DirectShow filter IIRC, but unfortunately there is no good encoding tool based on Dshow as of yet, and the future of Vdub 2 is pretty uncertain here ( Avery made some comments about Dshow in this respect recently ).
Main questions i'd love to see answered :
1. Sampling rate conversion : If any video encoding tool is calling an ACM audio codec ( like Fraunhofer MP3 ) for a specific sampling rate of the existing audio stream ( say 44100 Hz ) it will only show the list of those available that can handle this sampling rate on their input. Now, for a 44.1 Khz rate it will also show those that will output to a 22.05 Khz sampling rate, correct ? This is an indication to me that ACM does allow to have different sampling rates on input and output, but what about things like a 48 KHz to 44,1 KHz conversion, done with a BeSweet.ACM using SSRC in 32 bit FP mode, or even a SSRC.ACM ? Is the ACM codec allowed to write any value in the tag indicating sampling rate, or is this limited somehow ?
2. One pass normalizing : Using ReplayGain or MP3 gain it was maybe possible to perform one pass normalizing somehow ? No idea how its done though, i never understood replaygain good enough.
Think about capturing in Vdub guys !! Wouldnt it be great to have sound normalized on capturing automatically, when outputting to PCM WAV or MP3 ? How could we write the tag if capturing is finished ?
3. Muxing external audio files like AC3 or DTS into AVI from a BeSweet.ACM codec : The source file could be set in the configuration dialogue box somehow, and there you go muxing in any video editing application that can handle ACM codecs ...
I guess i am just dreaming here ... just look at it like a funny kind of brainstorming folks :D ....