sleepysaint's guide to adam to get into what.cd without invite

begging:

I got a list of possible interview questions from some forums. My

questions were a little different than these both times but I got

some of the same ones. I went through and detailed the correct

answers to each of these. You'd do well to study on formats but I

hope I've done the grunt work for you.
The bottom line is, they want to know that you understand what

transcoding is in all circumstances because they're really

intolerance of bad transcodes and lossy music. As such, you should

first be familiar with lossy and lossless audio formats.
Allowed on what.cd:
Lossless: FLAC, DTS (don't worry about DTS)
Lossy: MP3 at 192kb/s or GREATER. no less. Ogg. AAC. AC3. (don't

worry about AC3)
They'll probably ask you about formats not allowed on what too.
Lossless: FLAC, ALAC, APE, WAV(PCM), WMV, CDDA (CD audio)

Read about each of these formats on wiki. Some are container formats,

meaning they could contain various types of audio data.

http://wiki.hydrogenaudio.org/index.php?

title=LAME#Detailed_explanation_.28long_answer.29

That's your cheat sheet for MP3 bit rates.
The hydrogenaudio wiki has a lot of info on other things as well, so

read up.

**The sample questions follow. They might ask you a totally different

set of questions about different things, like putting formats in

order or who knows what. You can cheat and google or use whatever

resources you have handy to find the answer but it's a timed test so

you gotta be quick. These are here to show you a lot of repetitive

answers that should come quickly. The overarching point is Lossless-

>lossy = good and lossy->anything = BAD.


They're gonna ask you some preliminary questions, probably something

along the lines of the following:

1. Why are you interested in becoming a What member?
Because you like obscure music and you're interested in knowing the

quality of the music you get, right? Mention liking FLAC and lossless

music for bonus points

2. How often do you plan on using the site?
Tell the truth, if you're like me you'll use it all the time.

3. What kind of internet connection do you have?
They're gonna ask you before the interview to do a speedtest at

speedtest.net and send them a link to the screenshot. if you normally

run on wireless you might wanna wire into the wall when you do this,

just to improve ping. they'll accept it no matter what. just tell the

truth.

4. Are you a member of any other private trackers?
Have a screenshot of your demonoid stats and username uploaded

somewhere, link them.

5. How much experience do you have creating & uploading torrents?

Which BT client do you use?
Tell them the truth.

7. How big is your music/cd collection? What bitrates/formats? Where

did you get your collection (internet-where?/own rips-read ahead)
Tell them the truth.

8. What application do you usually use to rip CDs & how many you have

(estimate)?
Tell them you use Exact Audio Copy to rip CDs and if you've never

used it before then tell them that's what you plan to use.

9. What is the difference between a lossy & a lossless audio codec?
A lossless audio codec preserves all of the auditory information from

the source data. A lossy codec irretrievably loses some of the

auditory data due to compression, resulting in a lower quality sound

but a smaller file size.

10. What are VBR & CBR? Out of following pick the highest standard

LAME mp3 bitrate: 192, V0, V2, 320, V4, 512?
In Constant Bit Rate encoding, the bitrate is kept constant across

each sample of audio in the file. In Variable Bit Rate encoding, the

encoder (for instance, LAME encoder for MP3s) chooses the number of

bits per sample based on the auditory complexity. VBR typically

results in more efficient filesizes if comparing equal sound quality

between VBR and CBR. (if that last sentence is confusing ignore it)

Out of that list, 320CBR is the highest *standard* lame preset for

quality, because 512 isn't a LAME standard.

11. What is transcoding, in terms of audio? Transcoding is simply

converting a digital audio file from one format to another via a

codec. There are four types of transcodes that can happen between

digital files:
Lossless to lossless
Lossless to lossy
Lossy to Lossless
Lossy to Lossy

Of those, only the first two are allowed on what.cd, as the others

are considered "lossy transcodes".

12. Will these transcodes give the same result as if they were done

straight from an original cd? "YES" or "NO" for each one please.
a. 320 -> 192 no
b. V2 -> 192 no
c. 256 -> 256 no
d. 256 -> 320 no
e. wma -> mp3 yes
f. FLAC -> mp3 yes
g. mp3 -> Audio CD -> mp3 no
h. mp3 -> Audio CD -> FLAC no

The only time it will give the same result as if it came directly

from a CD is if it's a lossless format transcoded to something else.

ANY TIME you convert from one kind of mp3 to another, it's a bad

transcode. ANY TIME you burn a CD from mp3s and rerip it, it's a bad

transcode.

If no more than one lossless to lossy encoding is permitted which of

these transcodes are/is generally acceptable? Give only a YES or NO

for each specified example.
a. CDDA->WAV->CBR yes (WAV is lossless)
b. 320->WAV(PCM)->FLAC no (source 320 is lossy)
c. MP3->WMA->AAC no (source MP3 is lossy)
d. AAC->MP3->ALAC no (middle MP3->ALAC is lossy->lossless)
e. FLAC->APE->WAV(PCM) yes (all three are lossless)
f. APE->FLAC->APE yes (same as above)
g. FLAC->WAV(PCM)->CDDA yes (all three are lossless)
h. WAV(PCM)->ALAC->AAC yes (Lossless->lossless->lossy)
i. MP3->APE->FLAC no (source mp3 is lossy)
j. V0->CBR->WAV(PCM) no (two no-nos here)
k. CDDA->WAV(PCM)->MP3 yes
l. V2->V1->V3 no
m. V0->WAV(PCM)->CDDA no

I hope you get the idea? Remember these questions will be different.

2. Which conversions are acceptable without having *obvious* quality

loss? No more than one (1) lossless to lossy transcode is allowed to

take place. Answer Y (YES) or N (NO) to the following:

a. 192 MP3 -> 320 MP3 N
b. CDDA (CD) -> FLAC Y
c. 320 MP3 -> 192 MP3 -> q6 Vorbis (Ogg) N
d. FLAC -> CDDA (CD) -> 320 MP3 Y
e. APE -> FLAC -> q7 Vorbis (Ogg) Y
f. WAV (PCM) -> 256 MP3 -> APE -> FLAC N
g. V0 MP3 -> CDDA (CD) -> 320 AAC (MPA/MP4) -> WAV Absolutely NOT
h. ALAC (MPA/MP4) -> CDDA (CD) -> APE -> V2 MP3 -> FLAC no (the last

two are lossy to lossless)

got those from <@clockoutx> only got 5 right for this havn't changed

them so again up to you to find out them

1. How often will you use the site?
Be honest, I use it multiple times daily unlike any other music site

I've ever been on including demonoid.

2. How long will you seed for daily, and how long in total?
As long as you can, never stop seeding.

3. What is the concept of maintaing a ratio?
You know this.

4. Will you be able to maintain an acceptable ratio on What.cd? Can

you prove to me that you have been able to do this on other private

bittorrent sites?
You'll try your best by limiting your downloads until you've uploaded

your fair share.

1. Explain how lossy and lossless audio codecs are different Give

three examples of each.
This is a repeat question. I'll repeat what I said above: A lossless

audio codec preserves all of the auditory information from the source

data. A lossy codec irretrievably loses some of the auditory data due

to compression, resulting in a lower quality sound but a smaller file

size.

Lossy codec examples: AAC, Ogg vorbis, MP3
Lossless codec examples: FLAC, ALAC, APE

2. What is CBR & VBR? How are they different? Explain.
Repeat answer: In Constant Bit Rate encoding, the bitrate is kept

constant across each sample of audio in the file. In Variable Bit

Rate encoding, the encoder (for instance, LAME encoder for MP3s)

chooses the number of bits per sample based on the auditory

complexity. VBR typically results in more efficient filesizes if

comparing equal sound quality between VBR and CBR. (if that last

sentence is confusing ignore it)

3. What is v0?
V0 ("Preset Fast Extreme") is a VBR preset in the LAME mp3 encoder.

The target bit rate for V0 MP3 is 245kbit/s but obviously can vary.

4. What is the highest possible mp3 bitrate?
320kbit/s CBR is the highest possible using LAME encoder.

5. Give examples of methods that could be used to prove an audio file

is actually the type of format/bitrate advertised.
Using a program such as Audio Identifier will help, but one way that

works well is looking at the frequency spectrogram of the audio file.

If it has been transcoded from a lossy source, there should be

telltale signs (a distinct pattern or line at a lower frequency than

the claimed bitrate should cut off at).

6. - Define transcoding - In terms of audio.
Is it good or bad and why?
Are there good AND bad transcodes? Explain.
Transcoding is just converting digital audio data from one form to

another. Transcoding is good because it allows people to convert a

very large lossless format into something compressed/more manageable.

Without transcoding there would be no way to put your CD collection

on your iPod. But there are bad ways of transcoding - that is, taking

a lossy file such as an MP3 and transcoding it again. Since it has

already been compressed in a lossy format, any more transcoding done

to the file will result it a great loss of information and much

poorer sound quality. A good transcode is one that comes from a

lossless source, such as an original CD or a FLAC file.