In VOIP what is the simplest form of coding that samples & quantizes input signals w/o compression?
545386
The simplest form of digitally encoding a telephone bandwidth-limited speech signal is known as pulse code modulation, or PCM.
753807
To make your PC communicate with the phone line
359870
for analog transmission, wave form\nfor digital transmission, on and off bits
322778
Most software-based answering systems should have this capability (or even a low cost digital answering machine, if you don't want your computer running all the time).\n\nA quick check of Google and Yahoo for call recording software gives lots of results.
149765
Everyone is moving toward VoIP (Voice over IP) but if you want it now, i suggest checking out vonage.com.  it's the largest VoIP provider.
234469
Try Audacity, http://audacity.sourceforge.net/ and you will also need the LAME MP3 encoder, it's listed on the same site.
109519
There is by definition, two ways to compress any type of data:\n1. Lossy\n2. Lossless\n\nMost sound compression algorithms use lossy compression to compress the sound data.  It is reasonable to achieve 10x compression with little noticable loss of sound quality using a popular compression method such as MP3 or the more recent MP4 (which are actually both substandards of the MPEG specifications, for use in compressing video (moving picture) data).  The MPEG specs use a psycho-acoustic modelling technique in order to remove parts of the sound that are not noticable based on the limitations of human hearing.  For example, in a loud passage, a soft background sound will not be heard clearly and thus can be encoded using less bits.  There are also various ways of doing the encoding, using a fixed bit bucket (known as constant bit rate) or using a variable bit bucket, where bits can be traded based on time so that passages that are tougher to encode can use more bits (variable bit rate).\n\nLossless compression techniques generally fall under the same category as general compression algorithms such as those used for zipping files, etc.  However, sound does have certain characteristics that when exploited will allow better compression than a standard zipping of the PCM data would allow.  A good explanation of this type of technique can be found on the website linked below.  Because of the inherent randomness in sound data, typical lossless compression rates are about 2X.
75990
I use a program called\nKeep in mind that reencoding audio from one format to another may result in quality loss.\n\nBy searching versiontracker.com, I found a few programs, such as the freeware called 'Ogg Drop.'
34669
MPEG audio Layer-3 is correct. It is used to compress the file size.
765194
I assume you are talking about voice / recording and you already have a microphone or line input to your PC. I also assume you have Windows XP.\n\nYou can use the simple (very simple) Sound Recorder that comes with Windows XP: under Programs, Accessories, Entertainment.\n\nAlternatively, you can download freeware, such as Audacity (source below)
247585
Digital Compression\n\nOriginally most audio was recorded and distributed on CDs in the PCM format. The PCM file format consumes about 9 megabytes of file space for each minute of audio program length. Digital compression reduces the file size, and therefore the transmission time, of audio program material over a communications network such as the Internet.\n\nThere are two general types of digital compression - lossy and lossless:\n\nLossy Compression\nIn a lossy compression scheme, as the name implies, some of the original information is discarded when it is compressed. Therefore, it is impossible to produce an exact replica of the original audio signal when the audio is played. There are many different schemes of lossy compression available. These schemes generally provide varying compression ratios. The most popular of these, the MPEG Layer 3 (MP3) format, is commonly employed with compression ratios of up to ten to one. All lossy compression schemes add artifacts to the compressed audio. Artifacts are small imperfections created by the loss of the actual audio data. Although its quality may not seem that poor, the audio that has been processed by a lossy digital compressor is no longer "CD Quality".\n\nLossless Compression\nLossless compressors produce an exact replica of the original source. For example, the zip file format produced by the Winzip program on a PC produces exact copies of the original material that was encoded within the zip file. Fortunately, there is at least one lossless compression scheme available for Windows PCs. It's known as Shorten, an audio format that creates an exact clone of the original source. Lossless compression is the only way to preserve the "CD Quality" level of your program material.\n\nDo we still need digital compression in this high-speed world? For the time being, the audio you seek may only be available in compressed formats like MP3. We are rapidly approaching the time when we won't need to compress the audio in order to save transmission time or conserve disk storage space.\n\nOne proponent of Lossless Compression is Etree.org a music distribution hub but not for audio that has been compressed in a lossy fashion like MP3 or AAC but for audio that has been compressed in a lossless way. Etree.org uses the Shorten (.shn) audio compression format because it creates an exact clone of the original source.
457848
You could compress them using a program like winzip, then just send the one file and let the receivers decompress them.  Makes it quicker and easier.
541285
M$ has a free speech recognition api that you can just plug in.
563221
Vonage\nComcast\nTimeWarner\n...etc.
53783
Try Audio Hijack or Toast.
870367
Using the Calculator!! So simple and easy!!\n\nBy the way, what's this voip. I have heard a sweet dish of the same name. Ha ha just joking!!!
39354
Great question. And if you are planning to write your own CODEC (COder DECoder) for your own use, very cool.\n\nBe carefull though because the corporate owners of MP3 Thomson and Fraunhofer are ACTIVELY suing the pants of people big and small for infringing their patents.\n\nYou might want to consider patent and license free formats like OGG Vorbis, Speex, Flax, even Microsofts WMA!!!!!\n\nSounds like a cool project, even if you do decide to reverse engineer an MP3 codec just for your own totally cool learning project!