Tachyon <shiftyATATATsidehack.sat.gweep.net> writes:> [...] > p.s. I found this link on Randy Yates' page about noise-shaping... > > http://home.earthlink.net/~yatescr/noiseb.ps > > I think a line from that paper may answer Randy's question about > WHY you want to do this: > > "...quantisation of highly correlated signals (such as music) results > in tonal distortion components being added to the signal."Hey Tachyon, So you're assuming that the OP wants to do this in order to implement some sort of musical effect? An interesting possibility. My question was intended to be taken at face value. I was asking about the OP's intention, not implying that one shouldn't do such a thing. My gut feeling is that he wanted to create a 1-bit delta sigma bitstream (which won't happen if you merely convert to a 1-bit stream), but I don't really know. That's why I asked.> rock and roll, > -NHey Tachyon, nice screen name. I bet the Romulans don't like you too much, though... -- % Randy Yates % "The dreamer, the unwoken fool - %% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..." %%% 919-577-9882 % %%%% <yates@ieee.org> % 'Eldorado Overture', *Eldorado*, ELO http://home.earthlink.net/~yatescr
1-Bit Wave File?
Started by ●May 16, 2004
Reply by ●May 19, 20042004-05-19
Reply by ●May 19, 20042004-05-19
Tachyon wrote:> On 2004-05-18, Geoff Wood <geoff@paf.co.nz-nospam> wrote:> Additionally, square and PWM waveforms, staples of much electronic > music, are 1-bit waveforms.Bit-depth reducing to 1 bit does not convert PCM into a PWM signal. geoff
Reply by ●May 19, 20042004-05-19
Curious wrote:> I am looking for audio software that allows conversion of 16-bit WAVs > and 8-bit WAVs to 1-bit WAVs. I have used Adobe Audition and CakeWalk > Pyro. Neither of them work. CakeWalk does have a "bit-depth converter" > as a FX, however, when I try to use it, I get a runtime error and > Cakewalk automatically closes.A + Comparator FlipFlop I/P -------|\ +------+ Q | >----------| D Q|---+---- Bitstream out B +--|/ C +--|> | | | - | +------+ | | | | +-/\/\/\-----)-------------+ | R | C === | | Fs---+ 0V Several years ago I made a delay line to delay the audio for a walkie-talkie so that the Tx VOX voice operated switch and Rx unmute operation would be completed before the leading word spoken by the operator was transmitted. I tried a bucket brigade device (MN3001) but had troubles with noise and limitations on maximum delay. I tried the cct above as a 1-bit encoder (mentioned in a mag somewhere), clocked at over 200KHz. I do not know if the cct has a name. The Q o/p will be either high or low during a clk period, such as to force the RC LPF voltage at B to trend towards a match with i/p sig A. O/p Q tends to be strings of 1's or 0's until match is achieved, then become alternating 1's & 0's (50% PWM) until the i/p signal changes again. +------+ BitStream --->-----|D Q|--------> ZQ Delayed BitStream | | +------+ | | Fs----| |---->|/RAS | | |---->|/CAS | | |---->|/WE | | | | | | |---->|A0 | | PAL |-- |A1 | | |-- | " | | |-- | " | | |-- | " | | |---->|An | +------+ +------+ The above cct used a PAL to read the data bit at the current single bit wide DRAM chip address, the bit thus read having been written on the previous "lap" of the address counter. The PAL then operated /WE to write the current Bitstream i/p (0/1) into the current RAM address. The number of address lines & clock frequency determine the delay and fidelity which can be achieved. In your application this delay line block diagram could be implemented by 2 weeks of storage on your hard drive. R Delayed BitStream ------/\/\/\----+-----> Recovered audio | === C | 0V Recovery of the signal back to analog was by means of another RC LPF of identical time constant to the one used in the encoder. The idea is that if BitStream Q LPF's to imitate i/p signal A, then the identical but delayed BitStream ZQ should LPF to create a signal that looks like A also. I did once implement the above with a 56K DSP because I could not get samples of the intended ADC chip. It used software (RC LPF's etc.) for everything except the comparator (op-amp). It sort of worked, nearly, just about, almost, but the high interrupt rate interfered with other interrupt-driven processes, causing jitter & noise on the recovered audio. It did work well enough to get on with the job until the proper CODEC arrived. I think that using the above building blocks, you could write a prog to encode a WAV file & create a bitstream file. Converting back again should be quite simple. Jim Adamthwaite.
Reply by ●May 19, 20042004-05-19
Geoff Wood wrote:> Tachyon wrote: >> On 2004-05-18, Geoff Wood <geoff@paf.co.nz-nospam> wrote: > >> Additionally, square and PWM waveforms, staples of much electronic >> music, are 1-bit waveforms. > > Bit-depth reducing to 1 bit does not convert PCM into a PWM signal. >On the other hand, I guess it does, but not a PWM signal that has any relationship to the PCM-encoded waveform ! ;-) geoff
Reply by ●May 20, 20042004-05-20
Randy Yates <yates@ieee.org> wrote in message news:<u0yfes12.fsf@ieee.org>...> curious11112001@yahoo.com (Curious) writes: > > > I am looking for audio software that allows conversion of 16-bit WAVs > > and 8-bit WAVs to 1-bit WAVs. > > Why do you want to convert to a 1-bit WAV?I want film-quality sound. By "film quality" I am referring to the crackling [resembles the sound of burning coal] and lack of clarity in the audio recordings of old B&W films which used the variable-intensity recording. I would like to preserve the frequency response of CD-audio [keep the 44.1 KHz sampling rate], however, I would like to make it mono and film-quality in terms of the artifacts mentioned above. For some reason this type of music gets my juices going.
Reply by ●May 20, 20042004-05-20
"Curious" <curious11112001@yahoo.com> wrote in message news:34a4f456.0405191922.1d69cdf6@posting.google.com...> Randy Yates <yates@ieee.org> wrote in messagenews:<u0yfes12.fsf@ieee.org>...> > curious11112001@yahoo.com (Curious) writes: > > > > > I am looking for audio software that allows conversion of 16-bit WAVs > > > and 8-bit WAVs to 1-bit WAVs. > > > > Why do you want to convert to a 1-bit WAV? > > I want film-quality sound. By "film quality" I am referring to the > crackling [resembles the sound of burning coal]Random noise (of relatively specific types). Don't see how reducing quantization can accomplish this. There are actually recordings of "clean" noise that you can mix into your material to simulate this artifact.> and lack of clarity in > the audio recordings of old B&W films which used the > variable-intensity recording.Distortion, bandwidth restriction, etc. Distortion might be simulated by reducing bit-depth, but likely better ways. Of course true "1-bit" audio is indistinguishable from random noise.
Reply by ●May 20, 20042004-05-20
Curious wrote:> Randy Yates <yates@ieee.org> wrote in message news:<u0yfes12.fsf@ieee.org>... > >>curious11112001@yahoo.com (Curious) writes: >> >> >>>I am looking for audio software that allows conversion of 16-bit WAVs >>>and 8-bit WAVs to 1-bit WAVs. >> >>Why do you want to convert to a 1-bit WAV? > > > I want film-quality sound. By "film quality" I am referring to the > crackling [resembles the sound of burning coal] and lack of clarity in > the audio recordings of old B&W films which used the > variable-intensity recording. I would like to preserve the frequency > response of CD-audio [keep the 44.1 KHz sampling rate], however, I > would like to make it mono and film-quality in terms of the artifacts > mentioned above. For some reason this type of music gets my juices > going.You could probably reproduce that effect in more or less the manner it was first created by modulating a light bulb and detecting it with a photocell. I don't think the film added much but static from dirt, and you could probably get that by spraying dust through the beam. It actually might be a fun experiment. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form che...@prodigy.net.
Reply by ●May 20, 20042004-05-20
"Geoff Wood" <geoff@paf.co.nz-nospam> writes:> Geoff Wood wrote: >> Tachyon wrote: >>> On 2004-05-18, Geoff Wood <geoff@paf.co.nz-nospam> wrote: >> >>> Additionally, square and PWM waveforms, staples of much electronic >>> music, are 1-bit waveforms. >> >> Bit-depth reducing to 1 bit does not convert PCM into a PWM signal. >> > > On the other hand, I guess it does,Absolutely it does not. A PWM signal has the property that at time n*T the signal begins at a high state for p*T seconds and ends at a low state for (1-p)*T seconds, 0 <= p <= 1. A 1-bit bitstream does not have this property. Many people seem to have this misconception that a delta sigma bitstream is a PWM waveform. It is not - they are two different animals. -- % Randy Yates % "I met someone who looks alot like you, %% Fuquay-Varina, NC % she does the things you do, %%% 919-577-9882 % but she is an IBM." %%%% <yates@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://home.earthlink.net/~yatescr
Reply by ●May 20, 20042004-05-20
curious11112001@yahoo.com (Curious) writes:> Randy Yates <yates@ieee.org> wrote in message news:<u0yfes12.fsf@ieee.org>... >> curious11112001@yahoo.com (Curious) writes: >> >> > I am looking for audio software that allows conversion of 16-bit WAVs >> > and 8-bit WAVs to 1-bit WAVs. >> >> Why do you want to convert to a 1-bit WAV? > > I want film-quality sound. By "film quality" I am referring to the > crackling [resembles the sound of burning coal] and lack of clarity in > the audio recordings of old B&W films which used the > variable-intensity recording. I would like to preserve the frequency > response of CD-audio [keep the 44.1 KHz sampling rate], however, I > would like to make it mono and film-quality in terms of the artifacts > mentioned above. For some reason this type of music gets my juices > going.Hi Curious, That is a realistic goal, and I believe you can achieve it with some type of digital signal processing, but I don't believe simply reducing the bit-depth will accomplish the effect you're looking for. The problem is that the type of noise signal you want has a very different character than quantization noise. Quantization noise has a uniform probability distribution. What you want will have very large "tails" in its distribution. I am speaking here in terms that may be unfamiliar to you, but that should be familiar to a DSP engineer. I can't recall ever seeing any study or research that characterized the noise from a film soundtrack. Robert, have you ever seen this in your dealings with the AES? -- % Randy Yates % "Bird, on the wing, %% Fuquay-Varina, NC % goes floating by %%% 919-577-9882 % but there's a teardrop in his eye..." %%%% <yates@ieee.org> % 'One Summer Dream', *Face The Music*, ELO http://home.earthlink.net/~yatescr
Reply by ●May 20, 20042004-05-20
Curious wrote:> Randy Yates <yates@ieee.org> wrote in message news:<u0yfes12.fsf@ieee.org>... > >>curious11112001@yahoo.com (Curious) writes: >> >> >>>I am looking for audio software that allows conversion of 16-bit WAVs >>>and 8-bit WAVs to 1-bit WAVs. >> >>Why do you want to convert to a 1-bit WAV? > > > I want film-quality sound. By "film quality" I am referring to the > crackling [resembles the sound of burning coal] and lack of clarity in > the audio recordings of old B&W films which used the > variable-intensity recording. I would like to preserve the frequency > response of CD-audio [keep the 44.1 KHz sampling rate], however, I > would like to make it mono and film-quality in terms of the artifacts > mentioned above. For some reason this type of music gets my juices > going.You may be able to get this effect with a program like CoolEditPro which can merge a wide variety of distortion effects into your original sound. One of the built-in distortion settings may produce the type of sound you are after or you can create your own distortion. If you own one of these noisy films, record the sound from a section of film that has mostly noise and no audio. A program like CoolEditPro can extract the noise from the film section and merge it into any other sound file you have.
