請問 CD 轉成 file 會 lose 幾多?

tomtomsuccess · 發表於 2013-10-4 10:17

Raphael 發表於 2013-10-3 22:44
師兄，音樂 CD 嘅數據同一般 data CD 嘅數據唔同

Data CD 每個 file 都有詳細既 metadata，甚至傳送時每 ...

係你先咁好心機寫出來, 其實, google下都有, D人又唔做功課......

抵加你分.

tomtomsuccess · 發表於 2013-10-4 10:21

kc2wong 發表於 2013-10-3 23:33
Accurate rip 係 compare rip 出嚟file 嘅checksum ，好似MD5咁, 基本上係準嘅
其實我認同CAS嘅效果係比 ...

music CD did not record the master file's check sum data, so what's the point to compare the check sum data with different file from ripping?

PhantomGTR · 發表於 2013-10-4 10:52

本帖最後由 PhantomGTR 於 2013-10-4 10:53 編輯

睇了呢個 post 咁耐，終於係呢兩頁有些睇頭了。多謝師兄的科學資料提供，對大家玩 CAS 又是一大幫助！！{:9_421:}

ok102006 · 發表於 2013-10-4 11:03

本帖最後由 ok102006 於 2013-10-4 11:53 編輯

Audio CDs do not use WAV as their sound format, CD using Red Book audio instead.

CD 轉成 file 會 lose 幾多? In the conversion.

CD > PCM > WAV

Same apply to burn a WAV file to CD-R as audio CD:
WAV > PCM > CD

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CD 轉成 file 會 lose 幾多? Another lose may be in the computer CD-ROM pickup. How good is the len, error correction method, etc.

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Besides, some <CDs are mastered with pre-emphasis, an artificial boost of the treble or high frequencies. This serves to improve the apparent signal to noise ratio, by filtering out some the high frequency noise on playback. On playback, the player applies a low-pass filter to restore the frequency response curve to an overall linear one. Pre-emphasis time constants are 50uS or 15uS, and a binary flag in the disc subcode instructs the player to apply de-emphasis filtering if appropriate. Playback of such discs in a computer or 'ripping' to wave files typically does not take into account the pre-emphasis, so such files play back with a distorted frequency response.> That is why the CD sound may different or even better using Hi-Fi CD player when compare to CAS.

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7 more things to know about CAS...

1-multi-tasking - the computer CPU is multi tasking, very bad to sound quality.

2-quality of power - using Hi-Fi quality power supply will make a huge improvement.

3-quality of components - Hi-Fi CD player using audio grade transport, very good CD pickup lens, audio grade caps, audio grade cables, audio grade DAC with audio grade signal output (using transformer/Jfet/fet/opamp), audio grade PCB board (...etc) but CAS usually is using normal computer hardware.

4-software - different music playback software and OS has different sound (windows media player versus itunes versus foobar...windows versus apple versus linux etc)

5-interference - lots of components inside a computer, lots of interference generated. Bad to sound quality.

6-vibration - lots of components inside a computer and they will generate vibration. Bad to sound quality.

7-clock - Hi-Fi CD player has a very precise clock. Huge improvement to the sound quality.