How to cut file size by sampling freq, bit rate, stereo/mono

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cdeamaze
Posts: 87
Joined: Thu Oct 05, 2006 3:19 pm

How to cut file size by sampling freq, bit rate, stereo/mono

Post by cdeamaze »

In why are my files so big? the author posted a very interesting and challenging question. Subseuently piano nick posted a very practical answer
1. Length of file - time for file to play (assuming music). For wave files, it is approximately 11.0 MB per minute of song.

2. Type of file: Wave files are the largest; mp3 files and other types of compressed files vary depending upon the amount of compression and the audio codec used to compress them. MP3 files at 128 kbps will be about 1/9 th the length of a wave file (if my memory serves me correctly).
Let's take a look.
Here is a case study using "Red River Valley" (you may also Listen to "Red River Valley") as an example.

( I should really put them in a formatted table, it is very hard to read when they are NOT aligned. But I'm not allowed to use html, sorry! Chris, can I get your permission to use html? )
The following numbers are in this order:FN FS SF BR WL S/M
0 16 44.1 1411 16 S
1 8 44.1 706 16 M
2 4 44.1 352 8 M
3 1 11.025 88 8 M
4 .97 11.025 88 8 M
All the data are generated using GoldWave.(Thank you Chris, Great Product!) Actually, you can also verify these numbers by reasoning.

where
FN:File Number
FS:File Size, Mbytes
SF:Sampling Freq, KHz
BR:Bit Rate, kbps
WL:Word Length, bits
S/M:Stereo/Mono, S for Stereo, M for Mono

FN=0 Original file SF=44.1 16 bit stereo
FN=1 Reduced file SF=44.1 16 bit mono
FN=2 Reduced file SF=44.1 8 bit mono
FN=3 Reduced file SF=11.025 8 bit mono
FN=4 reduces file length by 5 sec from 135sec to 130sec, otherwise same as FN=3

The final file size before length modification for a 11.025 SF, 8-bit mono(FN=3) is 1M bytes which is reduced from original 16 M byte 44.1 SF, 16 bit stereo(FN=0) . By contrast, a compressed MP3 44.1 SF, 128 BR stereo is about 1.45M bytes(which is very close to piano nick's estimate 1.8M bytes, Great Call!). Then I noticed there is a 5 sec silence at the beginning of the song, which I removed by GoldWave again, resulting another 3% saving to get (FN=4) the absolute bottom at 970K bytes.

The bottom line is you can reduce your file size 33% below its MP3 format and still keep the song in wave format and a whopping factor of 16 from its original wave format. This is important if you want to place small files on the web but you can not get a mP3 player on your web page which is exactly what happened to me. Keep in mind you obtain the size saving at the expense of quality of your audio signal

GoldWave Inc.
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Re: How to cut file size by sampling freq, bit rate, stereo/

Post by GoldWave Inc. »

cdeamaze wrote:Chris, can I get your permission to use html?
Sorry, HTML is not permitted on this forum. You can use Code formatting instead:

Code: Select all

FN     FS       SF        BR     WL    S/M   
0      16      44.1      1411    16     S 
1      8       44.1       706    16     M
2      4       44.1       352     8     M
3      1       11.025      88     8     M
4     .97      11.025      88     8     M
Chris
Last edited by GoldWave Inc. on Sat Oct 28, 2006 1:35 pm, edited 2 times in total.

cdeamaze
Posts: 87
Joined: Thu Oct 05, 2006 3:19 pm

Table correction

Post by cdeamaze »

Thanks, Chris!
There is an error in the Code formatting: The first entry in FS should be 16 instead of 1 since the original file size is 16M bytes.

GoldWave Inc.
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Location: St. John's, NL
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Re: Table correction

Post by GoldWave Inc. »

Correction noted.

Chris

cdeamaze
Posts: 87
Joined: Thu Oct 05, 2006 3:19 pm

Re: Table correction

Post by cdeamaze »

Thanks again, Chris.

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