WAV is Microsoft (Microsoft) and development of a sound file format, it meets the RIFF (Resource Interchange File Format) file specification, used to store audio information resources in Windows platform, Windows platform and its application is widely supported by the The format also supports MSADPCM, CCITT A LAW and other compression algorithms, support for multiple audio digital, sampling frequency and channel, the standard format of the WAV file and CD formats, is 44.1K sampling rate, 16-bit quantization figures, so the quality and CD sound file is almost the same! Open the tool is WINDOWS WAV media player.
directory
Profile analysis feature supports converting pulse code modulation codec implementation of common use of VB in the Summary of OLE controls WAV MMControl control using the API function using VB About three parameters commonly used to represent sound, quantitative bits, sampling frequency and number of channels. Mono and stereo channels are divided, the sampling frequency generally 11025Hz (11kHz), 22050Hz (22kHz) and 44100Hz (44kHz) three, but despite the excellent sound quality, but in the compressed file size is too large! Relative to other audio formats is a disadvantage in terms of its file size is calculated as:
Wav File
Wav File
WAV format file share size (KB) = (sampling frequency X quantify the median X-channel) X time / 8 (byte = 8bit) currently supports WAV mobile phone designed primarily for smart phones, such as Sony Ericsson P910 and Nokia N90 and Dopod with Microsoft OS and other mobile phone, and other non-smart mobile phone products, support WAV format if the information is mostly belong to only support single channel. WAVE analysis is the standard used for recording WINDOWS file format, the file extension WAV file format is a joint development by Microsoft and IBM audio for digital storage standard, which uses RIFF file format structure, very close to the AIFF and the IFF format. Meet the RIFF (Resource Interchange File Format) specification. All have a WAV file header, the header of the audio stream encoding parameters. Table 1 WAV file header offset bytes 00H ~ 03H4 character types of content resources for the swap file logo (RIFF) 04H ~ 07H4 long integer starting from the next address to the end of the file's total number of bytes 08H ~ 0BH4 characters WAV files logo (WAVE) 0CH ~ 0FH4 wave format flag character (FMT) 10H ~ 13H4 filter byte integer (usually 00000010H) 14H ~ 15H2 integer format type (value is 1, said data PCMμ law encoded data) 16H ~ 17H2 integer channel the number of single-channel 1, dual-voice for the 218H ~ 1BH4 long integer sampling frequency 1CH ~ 1FH4 long integer waveform data transfer rate (the average number of bytes per second) 20H ~ 21H2 integer data adjustments (in bytes) 22H ~ 23H2-digit integer sample data table 2 WAV sound file offset number of bytes of data block types of content 24H ~ 27H4 character data identifier (data) 28H ~ 2BH4 long integer 2CH ...... WAV files sampled data as the most classic of the Windows Media Audio format is widely used, it uses three parameters to represent the sounds: sample median, sample frequency and number of channels. Mono and stereo channels are divided, the sampling frequency generally 11025Hz (11kHz), 22050Hz (22kHz) and 44100Hz (44kHz) three. WAV file share capacity = (sampling frequency × channel × sampling bits) × time / 8 (1 byte = 8bit). WAV on the audio stream encoding is not mandatory, in addition to PCM, there are almost all supported encoding specification ACM WAV audio stream that can be encoded. Multimedia applications using a variety of data, including bitmaps, audio data, video, data and peripheral device control information. RIFF for the storage of these types of data provides a method, RIFF file contains the data types from the file extension, can the data stored in RIFF files are: Audio Video Interleave format data (. AVI), wave format data (. WAV), the bitmap format data (. RDI), MIDI format data (. RMI), palette format (. PAL), multi-media film (. RMN), animated cursor (. ANI), the other RIFF files ( . BND). WAVE file format can store large amounts of data, usually audio encoding is pulse code modulation (PCM). WAV format from the Windows / Intel environment,
air force one low, and Little-Endian byte order used for storage. WAVE file as a multimedia file format used in one of the acoustic waves, which is based on the standard RIFF format. RIFF Resource Interchange File Format is the English abbreviation for each of the first four bytes of WAVE file is WAVE file header and data body by the two major components. Header which is divided into RIFF / WAV files and audio data format identification segment explanatory paragraph in two parts. WAVE file content and format of each part of the Annex. Common sound file there are two, corresponding to the mono (11.025KHz sampling rate,
nike air force one, 8Bit sample value) and dual-channel (44.1KHz sampling rate, 16Bit sample value). Sample rate refers to: the sound signal in the Each sample value is within the sound of analog signal sampling period, the integral value. For single-channel audio files, sample data for eight short integer (short int 00H-FFH); and for two-channel stereo sound files, each sampled data for a 16-bit integer (int), high eight, and Eight representatives of the low left and right channels, respectively. WAVE file data block contains a pulse code modulation (PCM) format samples. WAVE files are made by a sample of tissue. In the single-channel WAVE files, channel 0 represents the left channel, channel 1 represents the right channel. In the multi-channel WAVE file, samples are alternating. WAVE files are included in each sample in an integer i, i the length of the sample size required to accommodate the minimum specified number of bytes. Low significant byte stored first, that the bit rate of the sample on the i-bit high-effectively, and the rest of the position is 0, so 8-bit and 16-bit PCM waveform samples of the data format. WAVE file as a multimedia file format used in one of the acoustic waves, which is based on the standard RIFF format. RIFF Resource Interchange File Format is the English abbreviation for each of the first four bytes of WAVE file is WAVE files are composed by several Chunk. According to the occurrence in the document include: RIFF WAVE Chunk, Format Chunk, Fact Chunk (optional), Data Chunk. Specifically see below: --------------------------------------------- --- | RIFF WAVE Chunk | | ID = 'RIFF' | | RiffType = 'WAVE' | ---------------------------- -------------------- | Format Chunk | | ID = 'fmt' | ------------------- ----------------------------- | Fact Chunk (optional) | | ID = 'fact' | ------- ----------------------------------------- | Data Chunk | | ID = 'data '| ------------------------------------------------ Figure 1 Wav sample format contains Chunk RIFF WAVE Chunk
Figure 1 =============================== === | | Share bytes | details | ================================== | ID | 4 Bytes | 'RIFF' | ---------------------------------- | Size | 4 Bytes | | - --------------------------------- | Type | 4 Bytes | 'WAVE' | ------- --------------------------- Figure 2 RIFF WAVE Chunk to 'RIFF' as a mark, and then followed for the size field, the size is wav file size minus the ID and the number of bytes occupied by Size, the FileLen - 8 = Size. Then the Type field for the 'WAVE', Table
Figure 2
show a wav file. Structure is defined as: struct RIFF_HEADER {char szRiffID [4]; / / 'R', 'I', 'F', 'F' DWORD dwRiffSize; char szRiffFormat [4]; / / 'W', 'A', ' V ',' E '}; Format Chunk ======================================== ============================ | | bytes | details | ============= ================================================== ===== | ID | 4 Bytes | 'fmt' | ----------------------------------- --------------------------------- | Size | 4 Bytes | value of 16 or 18,18 are finally added Information | ------------------------------------------------ -------------------- ---- | FormatTag | 2 Bytes | encoding, usually 0x0001 | | ------------ -------------------------------------------------- ------ | | Channels | 2 Bytes | number of channels, 1 - Mono; 2 - Dual-channel | | ------------------ -------------------------------------------------- | | SamplesPerSec | 4 Bytes | sampling frequency | | --------------------------------------- ----------------------------- | | AvgBytesPerSec | 4 Bytes | number of bytes per second required | |===> WAVE_FORMAT ------------------------------------------------- ------------------- | | BlockAlign | 2 Bytes | block alignment units (number of bytes required for each sample) | | ------- -------------------------------------------------- ----------- | | BitsPerSample | 2 Bytes | bit number required for each sampling | | ----------------------- --------------------------------------------- | | | 2 Bytes | Additional information (optional, to determine whether by Size) | | ---------------------------------- ---------------------------------- ---- Figure 3 Format Chunk to 'fmt' as marked. Size is 16 under normal circumstances, when additional information is not final; if 18
Figure 3
then the last 2 bytes more than the additional information. Mainly made by some software wav format contains the two bytes of additional information. Structure is defined as: struct WAVE_FORMAT {WORD wFormatTag; WORD wChannels; DWORD dwSamplesPerSec; DWORD dwAvgBytesPerSec; WORD wBlockAlign; WORD wBitsPerSample;}; struct FMT_BLOCK {char szFmtID [4]; / / 'f', 'm', 't', '' DWORD dwFmtSize; WAVE_FORMAT wavFormat;}; Fact Chunk ================================== | | Share bytes | details | ================================== | ID | 4 Bytes | 'fact' | ---------------------------------- | Size | 4 Bytes | value is 4 | ----- ----------------------------- | data | 4 Bytes | | -------------- -------------------- Figure 4 Fact Chunk Fact Chunk is an optional field, generally when the wav file conversion software, made by some, is included in the Chunk. Structure is defined as:
Figure 4
struct FACT_BLOCK {char szFactID [4]; / / 'f', 'a', 'c', 't' DWORD dwFactSize;}; Data Chunk ==== ============================== | | Share bytes | details | ========= ========================= | ID | 4 Bytes | 'data' | --------------- ------------------- | Size | 4 Bytes | | ------------------------ ---------- | data | | | ---------------------------------- map 5 Data Chunk Data Chunk is the real place to save the wav data in order to 'data' as a marker of the Chunk. Then the size of the data. Wav data are followed. According to the number of channels in the Format Chunk and the sampling bit number, wav data bit can be divided into the following forms: For 8-bit single-channel, 8-bit data from each sample (bit) representation; for 8-bit stereo, each channels of data from an 8-bit (bit) data representation, and the first 8-bit (bit) data representation 0 channel (left) data, followed by the 8-bit (bit) data indicated that a channel (right ) data; for 16-bit single-channel, 16-bit data from each sample (bit) representation; placed high in the low byte, high byte low for 16-bit stereo store, each channel of data from a 16-bit ( bit) data representation, and the first 16-bit (bit) data representation 0 channel (left) data, followed by 16-bit (bit) data indicated that a channel (right) data. -------------------------------------------------- ------------------- | Mono | Sample 1 | Sample 2 | Sample 3 | Sample 4 | | |------------ -------------------------------------------- | 8bit quantization | channel 0 | Channel 0 | Channel 0 | Channel 0 | ------------------------------------ --------------------------------- | Stereo | Sample 1 | Sample 2 | | |---- -------------------------------------------------- - | 8bit quantization | channel 0 (left) | Channel 1 (right) | Channel 0 (left) | Channel 1 (right) | ---------------- -------------------------------------------------- --- | | Sample 1 | Sample 2 | | |---------------------------------- mono ---------------------- | 16bit quantization | Channel 0 | Channel 0 | Channel 0 | Channel 0 | | | (low byte) | (high byte) | (low byte) | (high byte) | -------------------------------- ------------------------------------- | | Sample 1 | | Dual Channel | --- -------------------------------------------------- --- | 16bit quantization | channel 0 (left) | Channel 0 (left) | Channel 1 (right) | Channel 1 (right) | | | (low byte) | (high byte) | ( low byte) | (high byte) | --------------------------------------- ------------------------------ Figure 6 wav data in bit position arrangement
Data Chunk header structure definition as follows: struct DATA_BLOCK {char szDataID [4]; / / 'd', 'a',
nike air force one high, 't', 'a' DWORD dwDataSize;}; features WAV audio formats include: simple encoding / decoding (almost direct memory from analog / digital converter (ADC) of the signal), general acceptance / support, and no loss of storage. The main disadvantage is that WAV format audio storage space required. The storage limit for small or small-bandwidth applications, this may be an important issue. WAV format Another potential drawback is the 32-bit WAV file 2G limitation, this limitation has been the development of the W64 for SoundForge format has been improved. Wav (1 sheets) the common use of PCM uncompressed WAV file encoding, which makes high quality WAV file, the volume is also unusually large, for the PCM WAV, perhaps the only lossless compression of audio to and that they have the same quality,
air force one shoes, usually we See what mp3, wma (excluding wmalossless) and wav's quality are far worse! This can be seen through the spectrum, even 320kbps in mp3 and wav a ratio, have a complex about! Supports Wav format support MSADPCM, CCITTALaw, CCITT μ Law and other compression algorithms, support for multiple audio bits, sampling frequency and channel, but its drawback is that larger files (one minute 44kHZ, 16bit Stereo WAV file about to be occupied by the about 10MB of hard disk space), it is not suitable for long records. In Windows, the sound files stored on your hard disk the extension WAV. WAV is a sound recording itself, so it accounts for a very large hard disk space. For example: 16-bit stereo sound 44.1KHZ takes a minute to about 10MB of capacity, and very much more backward than MIDI. Convert AVI, and WAV is the file structure is very similar, but more of a video stream AVI only. We are exposed to the AVI there are many, so we often need to install some Decode to watch some AVI, we are exposed to is a relatively large number of DivX video encoding, AVI DivX encoding can be used to compress video streams, of course, you can use other coding. Similarly, WAV audio can also use a variety of audio coding to compress the stream, but we are all common PCM encoded audio stream is processed WAV, does not mean that
Zen Wav player
WAV can only use PCM encoding, MP3 encoding also can be used in the WAV, and AVI, as long as installed the appropriate dDecode, can enjoy the WAV out. In the Windows platform, based on the PCM-encoded WAV is the best audio format support, support all audio software can be perfect, since they can achieve a higher quality requirements, therefore, WAV is the format of choice for creative music editing, save the music for material. Therefore, based on PCM coding is used as an intermediary WAV format, often used in the conversion into other encodings such as MP3 into WMA. WAV file format codec is a joint development by Microsoft and IBM audio for digital storage standard, which uses RIFF file format structure, very close to the AIFF and the IFF format. Multimedia applications using a variety of data, including bitmaps, audio data, video, data and peripheral device control information. RIFF for the storage of these types of data provides a method, RIFF file contains the data types from the file extension, can the data stored in RIFF files are: # Audio Video Interleave format data (. AVI) # waveform format data (. WAV) # data in bitmap format (. RDI) # MIDI format data (. RMI) # palette format (. PAL) # multi-media film (. RMN) # animated cursor (. ANI) # other RIFF files (. BND) RIFF is a nested data structure that contains the binary file format for each data structure is called a chunk (block). Chunk RIFF file is not in a fixed position, and therefore can not be used to locate the offset threshold. A block of data, including data structures, data flow, or other blocks (called sub-block), etc., each of RIFF block has the following structure: typedef struct _Chunk
VB VB to play WAV file interface
{DWORD ChunkId; / * block flag * / DWORD ChunkSize; / * block size * / BYTE ChunkData [ChunkSize]; / * block contents * /} CHUNK; ChunkId by the four ASCII characters to identify the block contains data. RIFF RIFF characters used to identify the data block, a space at the right intervals of not more than 4 characters of the ID. Because of this file structure was originally developed by Microsoft and IBM for the PC, as defined, RIFF file is little-endian byte order in accordance with written, but with big-endian byte order the file is to use 'RIFX' as a symbol. ChunkSize (block size) is stored in the ChunkData length of the data domain, ChunkId and ChunkSize domain size is not included in the limit. ChunkData (block content) data is contained in the word (WORD) arranged as a unit, if the data length is odd, then add a blank in the last (NULL) bytes. Sub-block (Subchunk) and the block has the same structure. A sub-block is included in the other blocks within a block, only the RIFF file block 'RIFF' and the list of blocks 'List' can contain sub-blocks, all other blocks can only contain data. A RIFF file is a RIFF block, file, all other blocks and sub-block are included in this block. WAV file format can store large amounts of data, usually audio encoding is pulse code modulation (PCM). WAV format from the Windows / Intel environment, and Little-Endian byte order used for storage. Pulse Code Modulation Claude E. Shannon in 1948 published In the same year Bell Labs engineers developed the PCM technology, although revolutionary at the time, but today is regarded as pulse code modulation is a very simple lossless encoding format, audio is collected at fixed intervals and to quantify the band value, and other applications using this encoding method, including telephone and CD. PCM There are three main ways: the standard PCM, differential pulse code modulation (DPCM) and adaptive DPCM. In the standard PCM, the band was quantified as the linear step frequency bands, used to store the absolute value. Stored in the DPCM is the difference between before and after the current value, thereby reducing the amount of storage about 25%. Adaptive DPCM DPCM change the quantization step, made in a given ratio of the letter (SNR) under the compressible more information. Implementation of common audio files in the WAV encoding and decoding process, the most consistent place, including sampling sites and sampling frame of the processing and conversion. Represents a sampling point within a given time, the audio signal, a sampling frame by the appropriate number of sampling points and can constitute a form of multiple channel audio signals. A sampling frame for stereo signals with two samples, one sample point corresponds to a channel. A sampling frame as a single unit to the D / A converter (DAC), to ensure that the correct signal can be sent simultaneously to the respective channel. Summary of the WAV VB development in the design of multimedia software, sound, multimedia is a very important element, excellent sound design for multimedia software considerably. The WAV format sound file is a sound file format most commonly used and most readily available, such as through the Win 95 in the VB is a very classic multimedia development tools to play WAV files in the VB methods are so few. Using OLE control to build a form, with the mouse to select the OLE control,
air force 1 shoes, OLE drag on the form region in the map window, select a new and sound and then press the OK button to finish adding OLE controls in the window. This can be attributes in the OLE control ResourceDoc select the file to play, the program runs you can double-click the OLE control. Which in the actual programming, often need to click on an icon or button to control sound playback, its implementation is like this: First, OLE control VISIBLE property to FALSE, then the icon or button click event write the following procedure: Private Sub Contol_Click () OLE1.Action = 7 End Sub VB5.0 using MMControl control provides many design of multimedia controls, in PROJECT / COMPENENTS / CONTROLS select MMControls controls, forms on the emergence of multimedia controls object, this object has different graphics on the logo, its name from left to right are the Pre, Next, Play, Pause, Back, Step, Stop, Record, Eject. The multimedia control can play a variety of sound formats, play WAV sound file format, the code Private Sub form_load () MMControl1.DeviceType = . Command = is activated, tap the button to play ding.wav file. In the actual software designs,
air force one low nike, more is the mouse click buttons or icons to control the playback of sound, its implementation is like this: First, the control MMControl VISIBLE property to FALSE, then the icon or button click event programs written in the following: Private Sub Control1_Click () MMControl1.Command = With a button or icon designed to replace the fixed multimedia control buttons, can design a more flexible and convenient user interface. Using VB's API functions of the form DECLARATIONS (statement), enter the following code: P rivate Declare Function sndPlaySound Lib a string variable that represents a WAV format file. 'UFlags set the playing status for the various options. Parameter value is 0X00, the synchronized playback, when the parameter value is 0X01 to achieve non-synchronous playback. At the command button's click event, enter the following code: Private Sub Command1_Click () Dim plays As Long plays = sndPlaySound (Play WAV files. term Atlas Atlas more open categories: video, file format, audio format, audio-visual me to perfect the
Hybrid Mode
