Broadcast wave (BWF)是 microsoft wave 的伸延, 主要是多了一些數據 metedata - 有如 ipod播放器裡的歌, 有專輯名,歌名, 歌者名..等等資料。 它和 wave 同樣有著 4G 理論上和 2G 實際上的限制, 為了超越這限制, 有兩種伸延格式(continue/link chunk )可幫助素材分佈到多個檔案, 播放器便會把它看成一個歌曲......
Broadcast wave 與 microsoft wave 的唯一分別是 檔案開始的伸延性資料 之不同(Bext-Chunk, Coding-History, etc...), 而BWF 也並不須要特別的播放器去播放........
WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. It is a variant of the RIFF bitstream format method for storing data in “chunks”, and thus also close to the IFF and the AIFF format used on Amiga and Macintosh computers, respectively. It is the main format used on Windows systems for raw audio.
Though a WAV file can hold compressed audio, the most common WAV format contains uncompressed audio in the pulse-code modulation (PCM) format. PCM audio is the standard audio file format for CDs, containing two channels of 44,100 samples per second, 16 bits per sample. Since PCM uses an uncompressed, lossless storage method, which keeps all the samples of an audio track, professional users or audio experts may use the WAV format for maximum audio quality. WAV audio can also be edited and manipulated with relative ease using software.
The WAV format is limited to files that are less than 4 GB in size, due to its use of a 32 bit unsigned integer to record the file size header (some programs limit the file size to 2-4 GB). Although this is equivalent to about 6.6 hours of CD-quality audio (44.1 kHz, 16-bit stereo), it is sometimes necessary to go over this limit, especially when higher sampling rates or bit resolutions are required. The W64 format was therefore created for use in Sound Forge. Its 64-bit header allows for much longer recording times. This format can be converted using the libsndfile library. The RF64 format specified by the European Broadcasting Union has also been created to solve this problem.
Broadcast Wave Format (BWF) is an extension of the popular Microsoft WAVE audio format and is the recording format of most file-based non-linear digital recorders used for motion picture and television production.
It was first specified by the European Broadcasting Union in 1997, and updated in 2001 and 2003.
The purpose of this file format is the addition of metadata to facilitate the seamless exchange of sound data between different computer platforms and applications. It specifies the format of metadata, allowing audio processing elements to identify themselves, document their activities, and permit synchronization with other recordings. This metadata is stored as extension chunks in a standard digital audio WAV file.
Files conforming to the Broadcast Wave specification have names ending with the extension .WAV.
In addition to the common WAVE chunks, the following extension chunks can appear in a Broadcast Wave file:
Since the only difference between a BWF and a "normal" WAV is the extended information in the file header (Bext-Chunk, Coding-History, etc...), a BWF does not require a special player for playback.
Unfortunately, this compatibility also preserves the filesize limitation that WAV files have (4 GB in theory, 2 GB in practice because most implementations use signed integer). In order to be able to store audio which would exceed this limit, 2 different chunks exist allowing to spread the audio material across several files: cont & link (see list above)
Since there is no official naming convention for these subsequent files, but it is still desirable to see at a glance which ones belong to a continuous piece of audio, a lot of programs apply a numbering scheme to the file suffix: .wav, .w01, .w02, ..., .wNN.
Each of those segments is a regular Wave/BWF file, but players that are aware of the continue/link chunk will treat all segments as one single, long piece of audio when opening the first segment ".wav".
As an extension, RF64 is a BWF-compatible multichannel file format enabling file sizes to exceed 4 GB that has been specified in 2006.
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Metadata are data about data. An item of metadata may describe an individual datum, or content item, or a collection of data including multiple content items.
Metadata (sometimes written 'meta data') is used to facilitate the understanding, characteristics, use and management of data. The metadata required for effective data management varies with the type of data and context of use. In a library, where the data is the content of the titles stocked, metadata about a title would typically include a description of the content, the author, the publication date and the physical location. In the context of a camera, where the data is the photographic image, metadata would typically include the date the photograph was taken and details of the camera settings. On a portable music player such as an iPod, the album names, song titles and album art embedded in the music files are used to generate the artist and song listings, and are metadata. In the context of an information system, where the data is the content of the computer files, metadata about an individual data item would typically include the name of the field and its length. Metadata about a collection of data items, a computer file, might typically include the name of the file, the type of file and the name of the data administrator.
Broadcast wave 與 microsoft wave 的唯一分別是 檔案開始的伸延性資料 之不同(Bext-Chunk, Coding-History, etc...), 而BWF 也並不須要特別的播放器去播放........
WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. It is a variant of the RIFF bitstream format method for storing data in “chunks”, and thus also close to the IFF and the AIFF format used on Amiga and Macintosh computers, respectively. It is the main format used on Windows systems for raw audio.
Though a WAV file can hold compressed audio, the most common WAV format contains uncompressed audio in the pulse-code modulation (PCM) format. PCM audio is the standard audio file format for CDs, containing two channels of 44,100 samples per second, 16 bits per sample. Since PCM uses an uncompressed, lossless storage method, which keeps all the samples of an audio track, professional users or audio experts may use the WAV format for maximum audio quality. WAV audio can also be edited and manipulated with relative ease using software.
The WAV format is limited to files that are less than 4 GB in size, due to its use of a 32 bit unsigned integer to record the file size header (some programs limit the file size to 2-4 GB). Although this is equivalent to about 6.6 hours of CD-quality audio (44.1 kHz, 16-bit stereo), it is sometimes necessary to go over this limit, especially when higher sampling rates or bit resolutions are required. The W64 format was therefore created for use in Sound Forge. Its 64-bit header allows for much longer recording times. This format can be converted using the libsndfile library. The RF64 format specified by the European Broadcasting Union has also been created to solve this problem.
Broadcast Wave Format (BWF) is an extension of the popular Microsoft WAVE audio format and is the recording format of most file-based non-linear digital recorders used for motion picture and television production.
It was first specified by the European Broadcasting Union in 1997, and updated in 2001 and 2003.
The purpose of this file format is the addition of metadata to facilitate the seamless exchange of sound data between different computer platforms and applications. It specifies the format of metadata, allowing audio processing elements to identify themselves, document their activities, and permit synchronization with other recordings. This metadata is stored as extension chunks in a standard digital audio WAV file.
Files conforming to the Broadcast Wave specification have names ending with the extension .WAV.
In addition to the common WAVE chunks, the following extension chunks can appear in a Broadcast Wave file:
- Original Bext chunk ('bext')
- iXML chunk ('iXML')
- Quality chunk ('qlty')
- MPEG audio extension chunk ('mext')
- Peak Envelope chunk ('levl')
- link chunk ('link')
- axml chunk ('axml')
- Continue chunk ('cont')
Since the only difference between a BWF and a "normal" WAV is the extended information in the file header (Bext-Chunk, Coding-History, etc...), a BWF does not require a special player for playback.
Unfortunately, this compatibility also preserves the filesize limitation that WAV files have (4 GB in theory, 2 GB in practice because most implementations use signed integer). In order to be able to store audio which would exceed this limit, 2 different chunks exist allowing to spread the audio material across several files: cont & link (see list above)
Since there is no official naming convention for these subsequent files, but it is still desirable to see at a glance which ones belong to a continuous piece of audio, a lot of programs apply a numbering scheme to the file suffix: .wav, .w01, .w02, ..., .wNN.
Each of those segments is a regular Wave/BWF file, but players that are aware of the continue/link chunk will treat all segments as one single, long piece of audio when opening the first segment ".wav".
As an extension, RF64 is a BWF-compatible multichannel file format enabling file sizes to exceed 4 GB that has been specified in 2006.
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Metadata are data about data. An item of metadata may describe an individual datum, or content item, or a collection of data including multiple content items.
Metadata (sometimes written 'meta data') is used to facilitate the understanding, characteristics, use and management of data. The metadata required for effective data management varies with the type of data and context of use. In a library, where the data is the content of the titles stocked, metadata about a title would typically include a description of the content, the author, the publication date and the physical location. In the context of a camera, where the data is the photographic image, metadata would typically include the date the photograph was taken and details of the camera settings. On a portable music player such as an iPod, the album names, song titles and album art embedded in the music files are used to generate the artist and song listings, and are metadata. In the context of an information system, where the data is the content of the computer files, metadata about an individual data item would typically include the name of the field and its length. Metadata about a collection of data items, a computer file, might typically include the name of the file, the type of file and the name of the data administrator.