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kc2wong 發表於 2013-10-4 13:43
It is only absolute correctness vs relative correctness. If majority get the same result, likely ...
Haha, your question simply is getting back to the first CD appeared in the world. We are actually listening digital music which is already LOSSY (so, in principal, what we are comparing, we have been listening LOSSY file since we have CD-DA, haha, it is just 16/44.1 for representing analogue signal) due to sampling . But from pyscoacoustic model, and the bandwidth and storage issues in 90's, compression is needed and thus huge compression gain can be done in frequency domain or the spectrum or exactly on the cepstrum, which is the basis of mp1, mp2 and finally the popular mp3 audio coding used the ISO/IEC standard in 90's.
So, if our discussion prolong, haha, one day, there should no Blu-ray as we will watch raw picture of frame size 1920x1080 which correspond to proximate the lines of 1080 film's scan lines (~HDTV). It use MPEG-4/H.26x family codec design with audio bitstream or lossless PCM for multiple channels! We can see no more compression technique is required in such huge storage and big bandwidth Era to audio source.
That's how VCD or MPEG-1 claiming to store moving picture of 320x240 or 352x288 (PAL or NTSC) in 90's. Thus, for a second of video at that time it requires 320x240 pixels x 3 Bytes (RGB or YCrCb:4:44:4) x 30 frames (NTSC) = 6912000Bytes ~or> 1 CD-ROM data storage!!! That's why VCD can store 1 hour of video we can say the compression ratio is of up to 60x60 times!
Relatively, mp2 is the associated coding format for VCD at that time. Storing MP2 or even MP3 is comparatively low demand, but we need quality! Cuz human sensation system can easily sense auditory noise easier than visual noise or defects. Where no one can imagine we can listen to such poor quality of MP3 in 90's and bought lots of different portable MP3 players. Until today, 10GB network, listing lossless music of even up to 32/384k, whereas 32 means 32bits or 2 to the power 32, which is a huge step size for representing the ampitude (-2,147,483,647 to +2,147,483,648) [c.f. -32767 to +32768 for 16 bit]. From our human ears, we sometimes can still feel the dynamic range of 16bits and claiming the human voice is too small volume comparatively to the background music, esp in Movie, or "not very smooth" enough... especially for scratched CDs or the resultant glitch, pop sound, but how about 24bits or 32bits, what is the sound of glitch or defacted surface of a scratched damaged CD? a smooth pop sound, haha. [利申,金耳仔我唔係.不過可能有人既聽覺可以勁到上"矛盾對決". 金耳仔vs HD audio ]
In short, as we have been already listening CD-DA, we are actually listening lossy reconstructed PCM to fake our ears that is the "original" from mastering in a high quality recording system/room. So, if the production is higher bit, higher sampling frequency, and you like the song, simply 科水 immediately. Otherwise if it again and again use various different CD media to tape down with CD-DA format (but not DSD, another story), why we need to buy it in expensive price, e.g. K2HD, AMCD, xxyyCD, answer is very simple, better quality of the disc, plastics, chemical, durable, ...etc.科水 again if we like
So if play CAS, probably chings like me is trying out DSD. It's time to play CAS 2.0, let me coin this name out haha! Take on your Jean 501 or recently LKS to pk the PCM 16/44.1 which should still tell different on PCM 16/44.1... 點都好,手上既rip檔咪大部份都係from CD-DA... Can a CAS2.0's DAC easily KO the previous DAC? I am now awaiting for my new 501...
Anyhow just my two cent 因office環境, 好難打中文快...岩睇加下分,小弟想升下level,哈哈.
P.S. the quality of burn an ISO cloned backup from a music disc (for backup purpose ar... ) is not the same as if you copy all the trackXX.cda to trackXX.wav and burn it again using CD-DA format. You can try, i tried long time ago, however, i don't know if today's CD-ROM or DVD-ROM or BD-ROM reading technique is better than the past, but still optical-2-digital issue happens. Thanks for reading 有錯物打我. |
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