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This section lists Media Kit functions that aren't contained in classes.
Declared in: be/media/MediaDefs.h
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Returns true if media data of format format1 can be fed into a consumer that accepts data in media_format format2; otherwise, returns false.
Declared in: be/media/MediaDefs.h
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If you need to search through all available file formats, you can do so using this function. Point cookie at an int32 containing 1, and info at a media_file_format structure, and call get_next_file_format(); on return, info will contain information about the first available file format.
You can call get_next_file_format() repeatedly until B_BAD_INDEX is returned, which indicates that there aren't any more file formats to scan.
The following snippet dumps a list of all the file formats, including all the audio and video codecs each file format supports.
void dump_info(void) {
int32 cookie = 0, cookie2;
media_format format, outfmt;
media_file_format mfi;
media_codec_info mci;
while(get_next_file_format(&cookie, &mfi) == B_OK) {
printf("%s (%s, id %d)n", mfi.pretty_name,
mfi.short_name, mfi.id);
cookie2 = 0;
memset(&format, 0, sizeof(format));
format.type = B_MEDIA_RAW_VIDEO;
format.u.raw_video.last_active = (uint32) (320 - 1);
format.u.raw_video.orientation = B_VIDEO_TOP_LEFT_RIGHT;
format.u.raw_video.pixel_width_aspect = 1;
format.u.raw_video.pixel_height_aspect = 3;
format.u.raw_video.display.format = B_RGB32;
format.u.raw_video.display.line_width = (int32) 320;
format.u.raw_video.display.line_count = (int32) 240;
format.u.raw_video.display.bytes_per_row = 4 * 320;
printf(" Video Encoders:n");
while (get_next_encoder(&cookie2, &mfi, &format, &outfmt, &mci) == B_OK) {
printf(" %s / %s (%d)n", mci.pretty_name, mci.short_name,
mci.id);
}
cookie2 = 0;
format.type = B_MEDIA_RAW_AUDIO;
format.u.raw_audio.format = media_raw_audio_format::B_AUDIO_UCHAR;
format.u.raw_audio.channel_count = 1;
printf(" Audio Encoders:n");
while (get_next_encoder(&cookie2, &mfi, &format, &outfmt, &mci) == B_OK) {
printf(" %s / %s (%d)n", mci.pretty_name, mci.short_name,
mci.id);
}
}
}
RETURN CODES
B_OK. A format was returned.
Declared in: be/media/MediaDefs.h
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launch_media_server() starts up the Media Servers (and the old Audio Server); you can use this if you discover that the Media Server isn't started but you need to use it.
shutdown_media_server() shuts down the Media Servers (and the old Audio Server). If you'd like to be able to keep track of the shutdown process, specify a pointer to a function in progress; this function will receive as input an integer value, stage, indicating how far through the shutdown process things are (100 means the shutdown is complete), message will be a test string describing what's going on, and cookie will be the same value as the cookie you specified as input into shutdown_media_server().
The shutdown process will abort if the timeout expires.
Declared in: be/media/MediaDefs.h
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Given the specified image, this function prepares the image for realtime media. The flags indicate what type of media the image will be handling; this must match the realtime flags specified by the BMediaRoster::SetRealtimeFlags() function (or by the Media preference application, which calls it). If the flags don't match up, B_MEDIA_REALTIME_DISABLED is returned.
RETURN CODES
B_OK. The image is ready for realtime media.
Declared in: be/media/MediaDefs.h
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Prepares the specified thread for realtime media. The stackUsed argument specifies how much of the stack should be locked down in memory. It's very unlikely that your thread actually uses the entire 256kB stack allocated for it, so you can preserve valuable system resources by indicating an upper bound for the amount of stack to lock in memory. If you need to lock down the entire stack, you can pass 0.
The flags argument indicates the type of media the thread will be handling.
RETURN CODES
B_OK. The image is ready for realtime media.
Derived from: be/media/PlaySound.h
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play_sound plays the sound file identified by the entry_ref pointed to by the soundRef parameter. The willMix and willWait arguments are used to determine how the function behaves with regard to other sounds.
Note that setting willMix to TRUE doesn't guarantee that your sound will play immediately. If the sound playback resources are claimed for exclusive access by some other process, you'll be blocked, even if you're willing to mix.
The background argument, if TRUE, tells the function to spawn a thread in which to play the sound. In this case, the function returns immediately. If background is FALSE, the sound is played synchronously and play_sound() won't return until the sound has finished.
The sound_handle value that's returned is a token that represents the sound that's being played back, and is only valid if you're playing in the background. You would use this token in a subsequent call to stop_sound() or wait_for_sound(). If the entry_ref doesn't represent a file, or if the sound couldn't be played, for whatever reason, play_sound() returns a negative integer.
Derived from: be/media/PlaySound.h
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stop_sound() stops the playback of a sound identified by handle, a value that was returned by a previous call to play_sound(). The return value can be ignored.
Declared in: be/media/MediaDefs.h
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Fills the buffer specified by outBuffer with a string describing the specified format. The buffer's size is specified by the bufferSize argument. The string may not be pretty, but it will list all kinds of interesting information about the format.
If a description is returned, this function returns true. Otherwise, the result is false.
Derived from: be/media/PlaySound.h
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Causes the calling thread to block until the sound specified by handle has finished playing. The handle value should be a value returned by a previous call to play_sound(). wait_for_sound() currently always returns B_OK.
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