Question for converting 8bit to 16bit wav?

[Frank]

Hi, all

Fro some reason,I need use Lame mp3 encoder to convert wav to mp3, But Since
Lame only receive 16bit Raw wave data so that I got a issue that how to
convert 8bit wav file to 16bit wav file, or say that how to convert 8bit Raw
Wave data to 16bit Raw Wave data. Many thanks =)

--
Frank F.Han

+-----------------------------------------+
| winsays@:-)hotmail:-).com |
+-----------------------------------------+

[Alessandro Angeli [MVP::DigitalMedia]]

Post by Frank
Hi, all
Fro some reason,I need use Lame mp3 encoder to convert
wav to mp3, But Since Lame only receive 16bit Raw wave
data so that I got a issue that how to convert 8bit wav
file to 16bit wav file, or say that how to convert 8bit
Raw Wave data to 16bit Raw Wave data. Many thanks =)

Actually, Lame 3.95.1 should support 8-bit PCM streams, both
raw (specifying the bit-width with the --bitwidth switch) or
wrapped in a RIFF/WAV structure (which is practically a
WAVEFORMATEX structure followed by the raw stream).

If you still want to do the conversion yourself, here is a
fragment of non-optimized C code to get you started:



typedef signed short PCM16;
typedef unsigned char PCM8;

PCM16 output[BUFFER_LENGTH];
PCM8 input[BUFFER_LENGTH];

/// if input_file is a WAV and not raw,
/// skip the header here

/// if output_file is a WAV and not raw,
/// write the empty header here

while(!eof(input_file)) {
fread(input,sizeof(PCM8),BUFFER_LENGTH,input_file);
for(int i = 0; i < BUFFER_LENGTH; i++) {
output[i] = ((PCM16)input[i] - 128) << 8;
}
fwrite(output,sizeof(PCM16),BUFFER_LENGTH,output_file);
}

/// if output_file is a WAV and not raw,
/// write the filled header here

[Frank]

Hi, Alessandro :p

Really really many many thinks! That's very kind of you. Thanks your reply,
thanks your time... You got so big help to me :p Thank you, and if you got
some more time, could you tell why(I wanna learn more) =)

Frank

Post by Alessandro Angeli [MVP::DigitalMedia]

Post by Frank
Hi, all
Fro some reason,I need use Lame mp3 encoder to convert
wav to mp3, But Since Lame only receive 16bit Raw wave
data so that I got a issue that how to convert 8bit wav
file to 16bit wav file, or say that how to convert 8bit
Raw Wave data to 16bit Raw Wave data. Many thanks =)

Actually, Lame 3.95.1 should support 8-bit PCM streams, both
raw (specifying the bit-width with the --bitwidth switch) or
wrapped in a RIFF/WAV structure (which is practically a
WAVEFORMATEX structure followed by the raw stream).
If you still want to do the conversion yourself, here is a
typedef signed short PCM16;
typedef unsigned char PCM8;
PCM16 output[BUFFER_LENGTH];
PCM8 input[BUFFER_LENGTH];
/// if input_file is a WAV and not raw,
/// skip the header here
/// if output_file is a WAV and not raw,
/// write the empty header here
while(!eof(input_file)) {
fread(input,sizeof(PCM8),BUFFER_LENGTH,input_file);
for(int i = 0; i < BUFFER_LENGTH; i++) {
output[i] = ((PCM16)input[i] - 128) << 8;
}
fwrite(output,sizeof(PCM16),BUFFER_LENGTH,output_file);
}
/// if output_file is a WAV and not raw,
/// write the filled header here
--
/**
* Alessandro Angeli
*
* MVP::DigitalMedia
*
* a dot angeli at biosys dot net
*/

[Alessandro Angeli [MVP::DigitalMedia]]

Post by Frank
Hi, Alessandro :p
Really really many many thinks! That's very kind of you.
Thanks your reply, thanks your time... You got so big
help to me :p Thank you, and if you got some more time,
could you tell why(I wanna learn more) =)

why what?

Post by Frank
Frank
"Alessandro Angeli [MVP::DigitalMedia]"

Post by Alessandro Angeli [MVP::DigitalMedia]

Post by Frank
Hi, all
Fro some reason,I need use Lame mp3 encoder to convert
wav to mp3, But Since Lame only receive 16bit Raw wave
data so that I got a issue that how to convert 8bit wav
file to 16bit wav file, or say that how to convert 8bit
Raw Wave data to 16bit Raw Wave data. Many thanks =)

Actually, Lame 3.95.1 should support 8-bit PCM streams,
both raw (specifying the bit-width with the --bitwidth
switch) or wrapped in a RIFF/WAV structure (which is
practically a WAVEFORMATEX structure followed by the raw
stream).
If you still want to do the conversion yourself, here is
typedef signed short PCM16;
typedef unsigned char PCM8;
PCM16 output[BUFFER_LENGTH];
PCM8 input[BUFFER_LENGTH];
/// if input_file is a WAV and not raw,
/// skip the header here
/// if output_file is a WAV and not raw,
/// write the empty header here
while(!eof(input_file)) {
fread(input,sizeof(PCM8),BUFFER_LENGTH,input_file);
for(int i = 0; i < BUFFER_LENGTH; i++) {
output[i] = ((PCM16)input[i] - 128) << 8;
}
fwrite(output,sizeof(PCM16),BUFFER_LENGTH,output_file);
}
/// if output_file is a WAV and not raw,
/// write the filled header here
--
/**
* Alessandro Angeli
*
* MVP::DigitalMedia
*
* a dot angeli at biosys dot net
*/

[tjfoe]

Alessandro Angeli [MVP::DigitalMedia] wrote on 02/22/2004 09:16 ET

Post by Alessandro Angeli [MVP::DigitalMedia]

Post by Frank
Hi, al
Fro some reason,I need use Lame mp3 encoder to conver
wav to mp3, But Since Lame only receive 16bit Raw wav
data so that I got a issue that how to convert 8bit wa
file to 16bit wav file, or say that how to convert 8bi
Raw Wave data to 16bit Raw Wave data. Many thanks =

Actually, Lame 3.95.1 should support 8-bit PCM streams, bot
raw (specifying the bit-width with the --bitwidth switch) o
wrapped in a RIFF/WAV structure (which is practically
WAVEFORMATEX structure followed by the raw stream)
If you still want to do the conversion yourself, here is
fragment of non-optimized C code to get you started
typedef signed short PCM16
typedef unsigned char PCM8
PCM16 output[BUFFER_LENGTH]
PCM8 input[BUFFER_LENGTH]
/// if input_file is a WAV and not raw
/// skip the header her
/// if output_file is a WAV and not raw
/// write the empty header her
while(!eof(input_file))
fread(input,sizeof(PCM8),BUFFER_LENGTH,input_file)
for(int i = 0; i &lt; BUFFER_LENGTH; i++)
output[i] = ((PCM16)input[i] - 128) &lt;&lt; 8
fwrite(output,sizeof(PCM16),BUFFER_LENGTH,output_file)
/// if output_file is a WAV and not raw
/// write the filled header her
/*
* Alessandro Angel
* MVP::DigitalMedi
* a dot angeli at biosys dot ne
*

Hi

I want to bring 24 Bit to 32 Bit signed long for playing 24/96 wav with my 3
Bit library. Could you please tell me, what I have to put in for &quot;x&quot
and &quot;y&quot; (below)

output[i] = ((PCM32)input[i] - x) &lt;&lt; y

May be you could give me any link to understand these numbers :-)

Thanks a lot
Regard
Thomas