Recording - Win32 Multimedia Programmer's Reference

Custom Search

Recording

The general MCI specification supports recording with digital-video, MIDI sequencer, video-cassette recorder (VCR), and waveform-audio devices; however, only waveform-audio and VCR devices currently implement recording capabilities. You can insert or overwrite recorded information into an existing file or record into a new file. To record to an existing file, open a waveform-audio device and file as you would normally. To record into a new file, when you open the device specify "new" as the device name if you are using the command-string interface. If you are using the command-message interface, specify a zero-length filename.

When MCI creates a new file for recording, the data format is set to a default format specified by the device driver. To use a format other than the default format, you can use the set (MCI_SET) command.

To begin recording, use the record command (or MCI_RECORD and the MCI_RECORD_PARMS structure).

If you record in insert mode to an existing file, you can use the "from" (MCI_FROM) and "to" (MCI_TO) flags of the record command to specify starting and ending positions for recording. For example, if you record to a file that is 20 seconds long, and you begin recording at 5 seconds and end recording at 10 seconds, the resulting file will be 25 seconds long. The file will have a 5-second segment inserted 5 seconds into the original recording.

If you record with overwrite mode to an existing file, you can use the "from" and "to" flags to specify starting and ending locations of the section that is overwritten. For example, if you record to a file that is 20 seconds long, and you begin recording at 5 seconds and end recording at 10 seconds, you still have a recording 20 seconds long, but the section beginning at 5 seconds and ending at 10 seconds will have been replaced.

If you do not specify an ending location, recording continues until you send a stop (MCI_STOP) command, or until the driver runs out of free disk space. If you record to a new file, you can omit the "from" flag or set it to zero to start recording at the beginning of a new file. You can specify an ending location to terminate recording when recording to a new file.

The record command is sometimes accurate to within only 1 second of the starting location, such as with VCR devices. To record more accurately, you should use the cue (MCI_CUE) command. This command is recognized by digital-video, VCR, and waveform-audio devices. For more information about recording with VCR devices, see VCR Services.

Saving a Recorded File
When recording is complete, use the save command (or MCI_SAVE and the MCI_SAVE_PARMS structure) to save the recording before closing the device.

Note If you close the device without saving, the recorded data is lost.

Checking Input Levels (PCM Only)
To get the level of the input signal before recording on a PCM (Pulse Code Modulation) waveform-audio input device, use the status (MCI_STATUS) command. Specify the "level" flag (or the MCI_STATUS_ITEM flag and set the dwItem member of the MCI_STATUS_PARMS structure to MCI_WAVE_STATUS_LEVEL). The average input signal level is returned. The left-channel value is in the high-order word and the right- or mono-channel value is in the low-order word.

The input level is represented as an unsigned value. For 8-bit samples, this value is in the range 0 through 127 (0x7F). For 16-bit samples, it is in the range 0 through 32,767 (0x7FFF).

Last news from Greatis Software

    Nostalgia .Net     .Net is powerful, but not all-powerful, so sometimes we need to use Win32 API for our .Net applications. It's simple enough with Platform Invoke if you have Win32 skill, but we do not always have time to dig the ancient documentation, declare the special types that are compatible with Win32, find the values of the Win32's constants and so on. Nostalgia .Net offers several simple-to-use classes, and components that will allow you to forget about the headache of Win32 and just use the power of Win32 in your application the same way as you use the native. Net classes. More »

Recommended software for developers

    Ultimate Pack     Component pack for Delphi and C++ Builder that contains runtime form designer, runtime object inspector, print suite and much more for the very special price. More »

    Form Designer .Net     Unique runtime form design solution that allows to edit any form in .Net WinForms application at runtime with full source codes for only 300 euro! More »

    Print Suite .Net     Print Suite .Net is a set of components for easy printing texts, images and grids from your WinForms applications. Full C# source codes are available More »

    Gradient Controls .Net     Gradient Controls .Net offers controls with gradient background feature. Labels, panels and so on... Full C# source codes are available More »

    Greatis iGrid     iGrid plots drawing grid right over your desktop, so you can use it everywhere, with any drawing application without any special plugins for different graphic editors. More »

All the contacts and projects

Dmitry Vasiliev (just.dmitry)

More Online Helps

Win32 Programmer's Reference
Win32 Multimedia Programmer's Reference
OLE Programmer's Reference
Microsoft Windows Pen API Programmer's Reference
Microsoft Windows Sockets 2 Reference
Microsoft Windows Telephony API (TAPI) Programmer's Reference
Unix Manual Pages

greatis just4fun network