Sets the codec (compression-decompression) of an audio control player.
object.SetCodec FormatTag Channels SamplesPerSec BitsPerSample
Parameter Description FormatTag Sets the format of the codec. If you want to use compression, GSM is recommended for the Internet and IMA ADPCM is recommended for corporate intranets.
Value Description 1 PCM (no compression) 2 Microsoft ADPCM 6 CCITT A-law 7 CCITT µ-law 17 IMA ADPCM (corporate intranets) 49 GSM610 (Internet) Channels Specifies the number of discrete channels in the format.
Value Description 1 Monaural data (recommended) 2 Stereo data SamplesPerSec Sets the samples-per-second rate in the format.
Value Description 8000 8 KHz (recommended) 11025 11.025 KHz 22050 22.050 KHz 44100 44.100 KHz BitsPerSample Sets the bits per sample in the codec format. The recommended value for compression is 0 for GSM, 4 for ADPCM, and 8 for PCM.
Value Description 0 Block-based codecs such as GSM (recommended for the Internet) 4 Sample-based codecs such as Microsoft ADPCM and IMA ADPCM (recommended for corporate intranets) 8 PCM (non-compressed)
This method does not return a value.
The SetCodec method is used to set the codec (compression-decompression) of the player. Using SetCodec overrides the value of AutoDetectCodec. Do not use SetCodec if you want to autodetect a codec.
Parameter values are not checked when SetCodec is called. If an invalid parameter is entered for SetCodec, an ERROR_TRANSFORM_NOT_SUPPORTED error will be generated.
GSM codecs are block-based, so a null value is entered, since "bits per sample" does not apply.
When a .wav file is sent using the NetShow Administrator application, the codec can be determined by the properties of the .wav file. Make sure that the player codec matches the .wav file codec.
Use the following settings for VAT (Visual Audio Tool) if you are using CCITT µ-law:
Setting Value Format Tag 7 Channels 1 Samples Per Second 8000 Bits Per Sample 8 Example
The following code example shows how to use SetCodec to play compressed IMA ADPCM audio (suggested for corporate intranets). The audio control object is called rtpaudio and a button has been created called BtnPlay. When the button is clicked, the codec specified in SetCodec will be set.
Sub BtnPlay_OnClick call rtpaudio.Stop() call rtpaudio.SetCodec(17,1,8000,4) call rtpaudio.SetSocket("239.240.100.2", 29102) call rtpaudio.Play() End Sub
Return to the RTP Audio Control Reference.
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