---
name: "pvftoadpcm4"
section: "1"
platform: "linux"
package: "mgetty"
version: "0.98-2"
release: "Debian 1.1 (Buzz)"
platforms: ["linux"]
url: "https://new.carta.tech/pvf"
---

# pvftoadpcm4(1)

utility programs for editing voice files

Part of [pvf(1)](/pvf/1.md).

## NAME

pvf - utility programs for editing voice files

## SYNOPSIS

**adpcmtopvf** *\[-r610\|-r601\]*

**pvftoadpcm3** *\[-r610\|-r601\]***, pvftoadpcm2** *\[-r612\|-r610\|-r601\]*

**pvftobasic, basictopvf**

**pvftolin** *\[-signed\|-16i\]***, lintopvf** *\[-signed\|-16i\] \[skip\]*

**pvftoau** *\[-ulaw\|-linear8\] \[rate\]***, autopvf** *\[-info\]*

**pvftovoc** *\[rate\]***, voctopvf** *\[-info\]*

**pvfamp** *amplification*

**pvfcut** *\[head\]* *tail*

**pvfecho** *\[delay\]* *\[volume\]*

**pvfmix** *filename*

**pvfreverse**

**pvfspeed** *speed* *\[exponent\]*

**pvfsine** *time* *frequency*

**pvffft** *\[-info\]* *\[-kill \<PID\>\]* *\<skip\>* *\<sample\_size\>* *\<thresh\>*

## DESCRIPTION

**Unless stated otherwise, these programs read a pvf voice file from** **stdin and write the modified result on stdout. pvf files are** **simply a stream of signed 16-bit integers (stored MSB first), they** **can easily be manipulated using cat and similar tools.**

## USAGE

- **adpcmtopvf** *\[-r610\|-r601\]*

  **Convert a ZyXEL ADPCM-2 or ADPCM-3 file to the internal pvf** **format. Note that there are two different versions of the adpcm** **format used by ZyXEL, it was changed with the introduction of** **the 6.10 ROM release. The default is specified in the Makefile** **to match your modem, the -r6xx flag can be used to override this** **default.**

- **pvftoadpcm2** *\[-r610\|-r601\]***, pvftoadpcm3** *\[-r610\|-r601\]*

  **Convert pvf format to ADPCM**

- **pvftobasic, basictopvf**

  **Conversion to/from \`audio/basic' as defined in RFC 1521 (MIME) as the** **"absolutely minimal lowest common denominator audio format.", which is** **8-bit ISDN uLaw (PCM) at a sampling rate of 8000 Hz.**

- **pvftolin** *\[-signed\|-16i\]***, lintopvf** *\[-signed\|-16i\] \[skip\]*

  **Conversion to/from linear samples. Default is 8 bit, the** *-16i* **flag is used for 16-bit files in intel byte order. Use the** *-signed* **flag to treat the samples as signed integers, default is unsigned.**

- **pvftoau** *\[-ulaw\|linear8\] \[rate\]*

  **Convert to SUN .au format. Default format is linear (16 bit),** **use -ulaw for 8-bit uLaw and -linear8 for 8-bit linear output. The** *rate* **is written into the file header, but it doesn't do any** **sampling rate conversion, use pvfspeed for that.**\

  **Since pvf samples are 16 bit wide and the ZyXEL sampling rate is 9600** **Hz, this is the default setting and it is directly supported by the** **Sun dbri(4) device. The defaults can be overridden; the only useful** **arguments for output on the Sun audioamd(4) device are \`-ulaw** **8000'.**

- **autopvf** *\[-info\]*

  **Convert from SUN .au format. The input file must** **have a valid .au header, supported formats are LINEAR\_16, LINEAR\_8 and** **MULAW\_8, single channel, unfragmented. Note that the sampling rate** **is ignored. The** *-info* **flag is used to print the file header** **information to STDERR.**

- **voctopvf** *\[-info\]***, pvftovoc** *\[rate\]*

  **Convert to/from \`Creative Voice' \*.VOC format. Only plain 8-bit** **unsigned samples are supported. The** *-info* **flag is used to print** **the file header information to STDERR. The optional** *rate* **is** **written into the voc header, the default is 9600 Hz.**

- **pvfamp** *amplification*

  **Multiply each sample by the floating point number** *amplification*

- **pvfcut** *\[head\]* *tail*

  **Cut off** *tail* **seconds from the end of the voice file (a negative** **number causes it to add a pause of the specified length). If two** **numbers are given, the first applies to the start and the second to** **the end of the data.**

- **pvfecho** *\[delay\]* *\[volume\]*

  **Add an echo delayed by** *delay* **seconds (default 0.15) with a** **relative volume of** *volume* **(default 0.3).**

- **pvfmix** *file*

  **Mix two pvf files. The data stream on stdin controls the** **length,** *file* **is truncated if it is longer. This is intentional,** **this way you can add background noises without having to match the** **lengths first. Note that you probably have to reduce the amplitude** **of the input files to avoid distortion due to overflow.**

- **pvfreverse**

  **Reverse the direction of the data stream.**

- **pvfspeed** *speed* *\[exponent\]*

  **Change the sampling rate.** *speed* **is a floating point number, 1.3** **corresponds to a 30% speedup. The optional** *exponent* **can be** **used for special effects (try 0.95 or 1.05).**

- **pvfsine** *time* *frequency*

  **Generate a sine wave with a frequency of** *frequency* **Hz and a** **duration of** *time* **seconds. Note that the frequency is calculated** **for a 9600 Hz sampling rate.**

- **pvffft** *\[-info\]* *\[-kill \<PID\>\]* *\<skip\>* *\<sample\_size\>* *\<thresh\>*

  **Do an fft on the voice data and return 0 for voice and 1 for data.** **This is intended to be used in the vg\_fft.in script.**

  *skip* **specifies the amount of data to skip before applying the** **fft, this is to give human callers time to start speaking. 1 second =** **9600 samples.**

  *sample\_size* **specifies the size of the sample tested via fft,** **must be a power of 2. 1 second = 9600 samples.**

  **The** *threshold* **is used for differentiating voice and data;** **data calls seem to have an index of 4 or lower, voice calls of 15 or** **higher.**

  **If the** *kill* **parameter is used, process** *PID* **will get a**  **SIGPIPE once pvffft has finished reading, and a SIGUSR2 if the** **sample is considered to be a data call.**

## EXAMPLES

**adpcmtopvf \<A \| pvfcut -1 .5 \| pvfmix B \| pvftoadpcm3 \>C**

**Read the adpcm file A, add one second of silence at the start** **and cut off the last half second, mix it with the pvf file B,** **convert the result to ADPCM-3 and store it in the file C.**

**adpcmtopvf \<A \| pvfspeed 1.2 \| pvftobasic \>B**

**Convert a voice message to a format suitable for inclusion in a MIME message.**

## AUTHOR

**Copyright (C) 1993 by Klaus Weidner**

**Sun .au conversion based on code by Craig Reese and Joe Campbell**

**ADPCM conversion based on the documentation by ZyXEL Communications Corporation**

**fft code by**