MS-ADPCM inserts silence at the end of my file[SOLVED]

[Kultag]

Hi.

Here’s what I do:

1. I extract an engine sound from a car’s sound pack for a game using its editor.
2. I open it for editing using Audacity.
3. Do the modifications, like amplification, cutting-out, copy-pasting, or similar.
4. I save it: Other uncompressed files → Header: WAV (MS), Encoding: ADPCM (see attachment).
5. I insert the new file into car’s sound pack using editor.
6. Now the sound file has a few tenth of a second silence at its end making the car’s in-game sound erratic (pause between every repeat of sound file).

How can I avoid this? Reopening the new sound file, and removing the silence didn’t help. Thanks.

Audacity 2.0.2, Win7 64b

[steve]

ADPCM was designed for telephony, so I’ll not be surprised if it is a limitation of the format. Could you use a different format such as Ogg or uLaw?

[Kultag]

@steve

Could you use a different format such as Ogg or uLaw?

Unfortunately no. The game only accepts this. The only thing I’ve been able to do is to copy-paste the useful engine sound segment several times so the pause would become more rare. But it is not always viable as the game limits the size of acceptable sound packages. With longer samples the modders are already close to the limit. However I don’t think Audacity inserts silence into each of the sound files, so there might more factors.

Here’s another topic I started about the same project of mine:

File size increases

Hi there. I extracted a wav file from a mod I downloaded for a game (see attachment). If I open it with Audacity (2.0.2, Win7 64), and save it without any changes (the other attachment), the file size gets 2 to 2.5 times bigger than the original. Both is mono, 44.1 kHz and 32 bit. File size is critical for the given game, so I’d like to keep it where it was (roughly). What’s happening? Thanx.

[Gale_Andrews]

ADPCM compression separates the waveform into blocks, so you have to cut on a block boundary to avoid silence at the end of the file: http://msdn.microsoft.com/en-us/library/windows/desktop/ee415711(v=vs.85).aspx .

I don’t know what block sizes Audacity uses, but at 44100 Hz, if you cut on a multiple of 4084 samples, you will export a complete file. See the attached (which still needs attention to sound “seamless”).

You can right-click over the Selection Toolbar digits to change the selection format to audio samples.


Gale

[Kultag]

Thanks, this might help, I’ll try it according to this.

[Kultag]

Solved. It works. Now I copy part of the useful section over the silence.

Thanks again.