Dramatically reducing file size of a WAV for an online game

[BillyBiggtime]

Hi guys,

I've written some music for an online game that comes in at roughly 7mins 20secs and produces a stereo WAV file of around 70MB at 44.1KHZ 16-bit. I've just been told by the game people that the piece they're replacing with mine is in WAV format but is only 400KB in size, and they need mine to be a relatively similar size - theirs is shorter, probably 2mins long, so mine would be longer but needs to be in the same ball park.

I've never had to go about producing a WAV file even close to that size before, and they definitely want it in WAV format, rather than MP3 or compressed formats. I'm at a bit of a loss. I know I can half the size by going mono. But how do I get it much smaller whilst still being a WAV and without just producing something that sounds horrible? Help!

Cheers!

[steve]

I've just been told by the game people that the piece they're replacing with mine is in WAV format but is only 400KB in size, and they need mine to be a relatively similar size - theirs is shorter, probably 2mins long

I don't think that is possible without looping.
2 minutes, mono, at 8000 Hz sample rate ADPCM encoded WAV (4 bit) comes in at 491.6 kB.

[BillyBiggtime]

I don't think that is possible without looping.
2 minutes, mono, at 8000 Hz sample rate ADPCM encoded WAV (4 bit) comes in at 491.6 kB.

That may explain how it was done with the piece of music they have then. I know mine will have to come in bigger as it is a long piece of music to start with. But if I could get it down to 2MB or less, that would be something. Is what you suggest the only way?

[steve]

I'd suggest that you get back in touch with the game people and ask them precisely what format they need the music in. You need to know:

• Number of channels (mono/stereo)
• Sample rate (usually one of: 8000, 11025, 16000, 22050, 32000, 44100)
• Bit depth (usually 4, 8, or 16)
• Bit format (Signed, Unsigned or Float)
• Encoding (Usually one of: PCM, A-law, u-law, Microsoft ADPCM, IMA ADPCM, GSM 6.10, G 721 ADPCM)

[BillyBiggtime]

I'd suggest that you get back in touch with the game people and ask them precisely what format they need the music in. You need to know:

• Number of channels (mono/stereo)
• Sample rate (usually one of: 8000, 11025, 16000, 22050, 32000, 44100)
• Bit depth (usually 4, 8, or 16)
• Bit format (Signed, Unsigned or Float)
• Encoding (Usually one of: PCM, A-law, u-law, Microsoft ADPCM, IMA ADPCM, GSM 6.10, G 721 ADPCM)

What is likely to most harm the sound quality, and what harms it least? Any recommendations? In terms of the encoding, I could only see 'WAV' (which I assume is PCM) and GSM 6.10 in Audacity. Would I need to download other plugins to enable these other formats? At the moment I've managed to produce a 16kHz 8-bit mono file that comes in at 6.67MB and it mostly sounds okay, but lots of hiss and a bit of distortion.

[BillyBiggtime]

I'd suggest that you get back in touch with the game people and ask them precisely what format they need the music in. You need to know:

• Number of channels (mono/stereo)
• Sample rate (usually one of: 8000, 11025, 16000, 22050, 32000, 44100)
• Bit depth (usually 4, 8, or 16)
• Bit format (Signed, Unsigned or Float)
• Encoding (Usually one of: PCM, A-law, u-law, Microsoft ADPCM, IMA ADPCM, GSM 6.10, G 721 ADPCM)

I'm beginning to suspect they may have made a mistake - given the relative quality of the file they're currently using. I just don't think that level of file size is possible without huge distortions and hiss on the file - I've managed to produce a 1.5MB file of my 7 mins plus of music, in WAV format, but it sounds terrible!

[steve]

What is likely to most harm the sound quality, and what harms it least?

Reducing the bit depth reduces the dynamic range? less bits = more hiss.
Reducing the sample rate reduces the frequency bandwidth: less samples per second = lower high frequency cut-off = duller sound.

ADPCM provides much better quality than would be expected from only 4 bits per sample, but it's by no means a "high quality" format.
U-Law, A-Law and the other fancy encodings are generally used for low bandwidth telecommunications where minimal decoding overhead is required - in other words, designed for "telephone quality".

PCM is the usual standard for high quality audio. 16 bit, 44.1 kHz (44100 samples per second) is the minimum requirement for "full quality" (around 20 Hz to 20 kHz bandwidth, and around -90 dB noise floor). This is the standard that was adopted for CD audio.

I could only see 'WAV' (which I assume is PCM) and GSM 6.10 in Audacity.

For the other options, select "Other uncompressed files" as the format, then click on the "Options" button.
More details here: http://manual.audacityteam.org/o/man/fi ... ialog.html

[kozikowski]

I'd suggest that you get back in touch with the game people

What did they say when you contacted them? Why are you replacing their original track? If theirs "sounded funny" when you may have found out why.
Koz

[BillyBiggtime]

I'd suggest that you get back in touch with the game people

What did they say when you contacted them? Why are you replacing their original track? If theirs "sounded funny" when you may have found out why.
Koz

Still waiting to hear back I'm afraid Koz. Theirs sounds fine - if you're on Facebook, look up the game Fraxinus and see what you think. I can't see that it is genuinely a 400KB WAV that's playing in the background there.

[steve]

The music is very repetitive, so perhaps they are sequencing a series of short audio clips., one for the bass, one for the bell, a couple for the vocal, etc. As a normal 16 bit 44.1 kHz mono WAV file the track would be about 22.7 MB (it's total duration before repeating is 4:17.385).

Perhaps they don't want to replace their music.