CD-AUDIO
a)type
b)bit depth
c)sample rate |
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a)PCM (pulse code modulation)
b)16-bit
c)44.1kHz |
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DVD-Audio (DVD-A)
1)type
2)bit depth
3)sample rate
4)other |
|
1. LPCM (Linear Pulse Code Modulation)
2. Bit Depth = 24-bit
3. Sample Rate = 96kHz
4. 5.1 Surround Sound |
|
| DVD stands for what?
What are its storage capabilities? |
|
Digital VERSATILE Disc
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4.7Gig (1-side, 1-layer)
to
17Gig (2-side, 2-layer) |
|
Super Audio Compact Disc (SACD)
1)type
2)bit depth
3)sample rate
4)other |
|
1. DSD (Direct Stream Digital)
2. Bit Depth = 1
3. Sample Rate = 2.8 MHz
4. 5.1 Surround Sound |
|
| Dynamic Range = (definition)
cd
dvd
sacd |
|
The range between the softest and
loudest sounds.
– CD = 96dB of dynamic range
– DVD = 146dB of dynamic range
– SACD = 120dB of dynamic range |
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Bit Rate Comparison (bit x sample)
1. LPCM
2. DSD |
|
2. DVD-A
24-bit x 96kHz = 2,304,000 bits per
second.
2. SACD
1-bit x 2.8MHz = 2,800,000 bits per
second. |
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|
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A. Audio compression designed specifically
for 5.1 surround sound.
B. Uses Perceptual Encoding
1. Takes advantage of “MASKING” across
all 6-channels.
2. The ear is less sensitive to those sounds, so Dolby Digital simply throws them out.
C. Dynamic Bit Allocation:
1. The system assigns bits from a common
bit pool to specific audio channels, based
upon the sound’s complexity and dynamic
range.
2. More dynamic range + more complex =
MORE BITS assigned to that channel |
|
MP3 (MPEG 1, Layer 3)
MPEG = ? |
|
A. MPEG = Motion Picture Experts Group
II: MP3 (MPEG 1, Layer 3)
B. MPEG 1 audio represents a family of three
CODEC’s called “layers.”
1. Layer 3 is the most complex and yields the
highest quality per bit-stream rate.
C. User can set the file size as a bit stream rate.
1. The range is between 32 and 320 kilobits per second
(kbps).
2. File size describes quality, from low-to-high.
3. Variable Bit Stream Rate (VBR):
a. Similar to Dynamic Bit Allocation. |
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|
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A. Breaks down (or encodes) audio in two different
computer languages, not as sample data.
III: MP4 (MPEG 4 Audio)
1. Kolmogorov Encoding:
a. Encodes audio as “directions” for
recreating the audio.
2. Two Languages:
a. SAOL (pronounced “sail”)
1. This is the sound modeling language.
b. SASL (pronounced “sassil”)
1. This is the sound sequencing language.
2. It is similar in concept to MIDI.
3. The “Cheese Cake” Analogy
a. An MP4 has the ingredients (SAOL) and the recipe
(SASL) for the cake.
b. The computer is the oven and bakes the cake. |
|
I. Video Tape
A)invented by who?
B)size
C)looks |
|
A. Invented by Ampex (Redwood City) in 1956.
B. It was a 2” industrial tape, not for consumers.
C. Looked a lot like 2” audio tape does today |
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Time Code:
A)invented by who?
B)what kinda clock? |
|
1. Invented by the Society Of Motion Picture And
Television Engineers (SMPTE) in 1967.
2. Gives a number to every frame.
a. Based on the 24-hour clock. |
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SMPTE Time Code
A)what is it?
B)time code word (howmany bits of info p/frame) |
|
A. An electronic reference signal recorded along
the entire length of the video tape.
B. Time Code Word:
1. 80-bits of information per frame of video. |
|
SMPTE 80 bit time code
howmany bits for
A)address track
B)user bits
C)sync word |
|
a. 32-bits are for the ADDRESS TRACK.
1. The address track is represented by
hours:minutes:seconds:frames
or HH:MM:SS:FF
b. 32-bits are for the USER BITS.
1. These are open bits of info to be
determined by the end user.
2. No pre-assigned value.
3. Can be used for copyright info,
dialog, lyrics, notes, etc.
c. 16-bits are for SYNC WORD.
1. Directional Information
Is tape moving forward or backward? |
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