- 第 2 页 -
對的......
When creating 20 or 24 bit files, the files can be stored in different formats.
The packed format actually stores the data in 3 bytes per sample, which allows for a max of 24 bits.
The unpacked format stores the data in a full DWORD (4 bytes per sample), which allows for a max of 32 bits, and therefore the filesize is actually larger.
The unpacked format was something I created as an extension into the future when the bit resolution grows beyond 24 bits. It can sometimes also possibly improve performance due to the fact that our current Pc's access data in DWORD chunks and the packed format requires multiple register shifts to compact and expand the data into the odd size 3 byte format, which translates into more internal manipulation to access each sample.
In most situations the difference may not be noticable.
For compatibility with other 24 bit wav files in most other software, you should use the default packed format.
Bob L
When creating 20 or 24 bit files, the files can be stored in different formats.
The packed format actually stores the data in 3 bytes per sample, which allows for a max of 24 bits.
The unpacked format stores the data in a full DWORD (4 bytes per sample), which allows for a max of 32 bits, and therefore the filesize is actually larger.
The unpacked format was something I created as an extension into the future when the bit resolution grows beyond 24 bits. It can sometimes also possibly improve performance due to the fact that our current Pc's access data in DWORD chunks and the packed format requires multiple register shifts to compact and expand the data into the odd size 3 byte format, which translates into more internal manipulation to access each sample.
In most situations the difference may not be noticable.
For compatibility with other 24 bit wav files in most other software, you should use the default packed format.
Bob L
另外一位朋友問及錄音時是否應選擇 24/96
Obviously, you require more disk space and more cpu overhead to manipulate that much more data.
Its not so obvious whether you can really hear any beneficial results in the end, especially if you have to take the project back down to 44.1 for CD reproduction... now you introduce more processing and possible artifacts with whatever conversion method you choose...
You may be surprised how smooth and clean a project kept in the SAWStudio environment from start to finish can sound at 44.1 the whole way...
But... if you can afford the converters and the time to experiment... SAWStudio will allow you to go up to 400k and 24 bits... so enjoy the ride.![]()
Bob L
Obviously, you require more disk space and more cpu overhead to manipulate that much more data.
Its not so obvious whether you can really hear any beneficial results in the end, especially if you have to take the project back down to 44.1 for CD reproduction... now you introduce more processing and possible artifacts with whatever conversion method you choose...
You may be surprised how smooth and clean a project kept in the SAWStudio environment from start to finish can sound at 44.1 the whole way...
But... if you can afford the converters and the time to experiment... SAWStudio will allow you to go up to 400k and 24 bits... so enjoy the ride.
Bob L
如果要用 DITHER , 要到最後最後最後導出才用.........當然也可以不用, 直接導出16/44,
也可把本來較高採樣的工程在 SAW 設為 16/44 然後直接導出 16/44.......
或 把工程對應原來音軌較高的採樣, 導出時 選16/44 同時也選 DITHER 1、2或3 > 導出
http://www.audiobar.net/viewthread.php?tid=119321&highlight=DITHER
[ 本帖最后由 himhui 于 08-8-25 15:26 编辑 ]
也可把本來較高採樣的工程在 SAW 設為 16/44 然後直接導出 16/44.......
或 把工程對應原來音軌較高的採樣, 導出時 選16/44 同時也選 DITHER 1、2或3 > 導出
http://www.audiobar.net/viewthread.php?tid=119321&highlight=DITHER
[ 本帖最后由 himhui 于 08-8-25 15:26 编辑 ]
回复 margindge 的帖子
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据我了解,unpacked是为了以后重采样到更高bit率而用,一般情况用packed即可
我又看了一下鲍比老爷子的意思，他貌似还是说4byte unpacked和 3byte packed 的问题。
4byte unpacked，其实就是24位采样位深用填零的方式（24Bit填零到32位，实际不会损失），变成32Bit总线传输模式。这样形如PCI总线会一次传输完成32Bit数据。他设置这个模式，估计是让用家将24Bit填零成32Bit，为一些设备提高传输效率而定。（RME音频卡直接支持这种传输模式）
而3byte packed，则是我们保存为兼容我们大多数专业声卡24Bit分批传输数据包规格。也就是说，为挤满32位总线，传输时，会将24Bit数据分批传输：24->8->16->16->8->24....如此循环。