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CMM-318-01 |
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Announcements: - I'll be in the lab Tuesdays and Thursdays from 1:00 PM - 4:00 PM. You are all welcome to stop by and get some practice time in on the workstations or to ask questions. - Sign up for other times in Rm. 442 (Classroom Services upstairs) They'll need 24 hours advance notice to schedule a TA. You might need to be a little flexible with the schedule. They like to be out of there by 8:00 PM. Sean Connelly knows the administration or our systems if you have problems. If you run into other problems with the program or hardware or just plain confusion... write it down. Email me. I'll get back to you. Don't worry, nothings an emergency... yet.
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Here is a link to download the Pro Tools Reference Guide. From the list of downloads choose: Pro Tools Reference Guide v7.4 (English) That's the version you want. It's freaking HUGE. 29.49 MB. 965 pages of hyperbole. So here's my tip of the day. Start on page 109 Chapter 9: Pro Tools Main Windows. If you familiarize yourself with all the buttons on those two main windows, life will be a whole lot easier.
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We've been throwing around some terms in class about types of audio files. Basically, we only listen to and use two kinds: wave (.wav) files (like on a CD) and the ever popular MP3 files. Here's some info for you.Audio Files - Music, voice, sound effects, even the audio that is embedded on a DVD or video is a digital sample of an analog sonic wave. It is saved to the computer and stored, like your other documents and files, in folders. There are many standards and formats of these audio files. We will only be using a few of the most commonly used formats. I will highlight those, but you should make yourself aware of the other types, so you can recognize them if they show up someplace. Ill show you how to convert one file type to another so you can use it in ProTools or another application. So, with a little help from Wikipedia
When we record to the computer (or another digital recorder) we sample the audio. In other words, take a reading of the input voltage which correlates to the input sound wave. The microphone picks up the vibrations from the air. The diaphragm of a dynamic microphone (or a plate on a condenser microphone) will vibrate at the same frequency and amplitude as the sound. The computer will store all these little samples, each one a quick picture of the sound wave at a given instant. CD audio has a sampling rate of 44k and a bit resolution of 16. So its audio will have 44,100 samples or pictures stored every second. And will store each one of these samples as a 16 bit word. (example: 1010101010100011) A higher bit resolution would have 24 ones and zeroes as a stored sample, giving a higher quality picture.) This data can then be stored uncompressed, or compressed to reduce the file size.
Types of formats Uncompressed audio formats: WAV, AIFF and AU Formats with lossless compression: Apple Lossless & lossless Windows Media Audio (WMA). FLAC, Monkey's Audio (filename extension APE), WavPack (filename extension WV), Shorten, Tom's lossless Audio Kompressor (TAK), TTA, ATRAC Advanced Lossless, Formats with lossy compression: Windows Media Audio (WMA) and AAC. MP3, Vorbis, Musepack, ATRAC, Uncompressed audio formatThere is one major uncompressed audio format, PCM, which is usually stored as a .wav on Windows or as .aiff on Mac OS. WAV is a flexible file format designed to store more or less any combination of sampling rates or bitrates. This makes it an adequate file format for storing and archiving an original recording. A lossless compressed format would require more processing for the same time recorded, but would be more efficient in terms of space used. WAV, like any other uncompressed format, encodes all sounds, whether they are complex sounds or absolute silence, with the same number of bits per unit of time. As an example, a file containing a minute of playing by a symphonic orchestra would be the same size as a minute of absolute silence if they were both stored in WAV. If the files were encoded with a lossless compressed audio format, the first file would be marginally smaller, and the second file taking up almost no space at all. However, to encode the files to a lossless format would take significantly more time than encoding the files to the WAV format. Recently some new lossless formats have been developed (for example TAK), which aim is to achieve very fast coding with good compression ratio. The WAV format is based on the RIFF file format, which is similar to the IFF format. BWF (Broadcast Wave Format) is a standard audio format created by the European Broadcasting Union as a successor to WAV. BWF allows metadata to be stored in the file. See European Broadcasting Union: Specification of the Broadcast Wave Format A format for audio data files in broadcasting. EBU Technical document 3285, July 1997. This format is the primary recording format used in many professional Audio Workstations used in the Television and Film industry. Stand-alone, file based, multi-track recorders from Sound Devices[1], Zaxcom[2], HHB USA[3], Fostex, and Aaton[4] all use BWF as their preferred file format for recording multi-track audio files with SMPTE Time Code reference. This standardized Timestamp in the Broadcast Wave File allows for easy synchronization with a separate picture element.
Lossless audio formatsLossless audio formats (such as the most widespread[5] FLAC, WavPack, Monkey's Audio, ALAC/Apple Lossless) provide a compression ratio of about 2:1. Free and open file formatswav standard audio file container format used mainly in Windows PCs. Commonly used for storing uncompressed (PCM), CD-quality sound files, which means that they can be large in size around 10 MB per minute. Wave files can also contain data encoded with a variety of codecs to reduce the file size (for example the GSM or mp3 codecs). Wav files use a RIFF structure. aiff the standard audio file format used by Apple. It is like a wav file for the Mac. ogg a free, open source container format supporting a variety of codecs, the most popular of which is the audio codec Vorbis. Vorbis offers compression similar to MP3 but is less popular. flac a lossless compression codec. This format is a lossless compression as like zip but for audio. If you compress a PCM file to flac and then restore it again it will be a perfect copy of the original. (All the other codecs discussed here are lossy which means a small part of the quality is lost). The cost of this losslessness is that the compression ratio is not good. Flac is recommended for archiving PCM files where quality is important (e.g. broadcast or music use). mpc - Musepack or MPC (formerly known as MPEGplus, MPEG+ or MP+) is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160180 kbit/s. Musepack and Ogg Vorbis are rated as the two best available codecs for high-quality lossy audio compression in many double-blind listening tests. Nevertheless, Musepack is even less popular than Ogg Vorbis and nowadays is used mainly by the audiophiles. raw a raw file can contain audio in any codec but is usually used with PCM audio data. It is rarely used except for technical tests. au the standard audio file format used by Sun, Unix and Java. The audio in au files can be PCM or compressed with the μ-law, a-μlaw or G729 codecs. mid - an industry-standard protocol that enables electronic musical instruments, computers, and other equipment to communicate, control, and synchronize with each other Open file formatsgsm designed for telephony use in Europe, gsm is a very practical format for telephone quality voice. It makes a good compromise between file size and quality. Note that wav files can also be encoded with the gsm codec. dct A variable codec format designed for dictation. It has dictation header information and can be encrypted (often required by medical confidentiality laws). vox the vox format most commonly uses the Dialogic ADPCM (Adaptive Differential Pulse Code Modulation) codec. Similar to other ADPCM formats, it compresses to 4-bits. Vox format files are similar to wave files except that the vox files contain no information about the file itself so the codec sample rate and number of channels must first be specified in order to play a vox file. aac the Advanced Audio Coding format is based on the MPEG2 and MPEG4 standards. aac files are usually ADTS or ADIF containers. mp4/m4a MPEG-4 audio most often AAC but sometimes MP2/MP3 mmf - a Samsung audio format that is used in ringtones. Proprietary formatsmp3 the MPEG Layer-3 format is the most popular format for downloading and storing music. By eliminating portions of the audio file that are essentially inaudible, mp3 files are compressed to roughly one-tenth the size of an equivalent PCM file while maintaining good audio quality. wma the popular Windows Media Audio format owned by Microsoft. Designed with Digital Rights Management (DRM) abilities for copy protection. atrac (.wav) the older style Sony ATRAC format. It always has a .wav file extension. To open these files simply install the ATRAC3 drivers. ra a Real Audio format designed for streaming audio over the Internet. The .ra format allows files to be stored in a self-contained fashion on a computer, with all of the audio data contained inside the file itself. ram a text file that contains a link to the Internet address where the Real Audio file is stored. The .ram file contains no audio data itself. dss Digital Speech Standard files are an Olympus proprietary format. It is a fairly old and poor codec. Prefer gsm or mp3 where the recorder allows. It allows additional data to be held in the file header. msv a Sony proprietary format for Memory Stick compressed voice files. dvf a Sony proprietary format for compressed voice files; commonly used by Sony dictation recorders. IVS A proprietary version with Digital Rights Management developed by 3D Solar UK Ltd for use in music downloaded from their Tronme Music Store and interactive music and video player. m4p A proprietary version of AAC in MP4 with Digital Rights Management developed by Apple for use in music downloaded from their iTunes Music Store. iklax An iKlax Media proprietary format, the iKlax format is a multi-track digital audio format allowing various actions on musical data, for instance on mixing and volumes arrangements. mxp4 a Musinaut proprietary format allowing play of different versions (or skins) of the same song.
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