MovieAudioCursor

from panda3d.core import MovieAudioCursor

class MovieAudioCursor

Bases: TypedWritableReferenceCount

A MovieAudio is actually any source that provides a sequence of audio samples. That could include an AVI file, a microphone, or an internet TV station. A MovieAudioCursor is a handle that lets you read data sequentially from a MovieAudio.

Thread safety: each individual MovieAudioCursor must be owned and accessed by a single thread. It is OK for two different threads to open the same file at the same time, as long as they use separate MovieAudioCursor objects.

Inheritance diagram

__init__(*args, **kwargs)

aborted()

C++ Interface: aborted(MovieAudioCursor self)

/**

• If aborted is true, it means that the “ready” samples are not being

• replenished. See the method “ready” for an explanation.

*/

audioChannels()

C++ Interface: audio_channels(MovieAudioCursor self)

/**

• Returns the number of audio channels (ie, two for stereo, one for mono).

*/

audioRate()

C++ Interface: audio_rate(MovieAudioCursor self)

/**

• Returns the audio sample rate.

*/

audio_channels()

C++ Interface: audio_channels(MovieAudioCursor self)

/**

• Returns the number of audio channels (ie, two for stereo, one for mono).

*/

audio_rate()

C++ Interface: audio_rate(MovieAudioCursor self)

/**

• Returns the audio sample rate.

*/

canSeek()

C++ Interface: can_seek(MovieAudioCursor self)

/**

• Returns true if the movie can seek. If this is true, seeking is still not

• guaranteed to be fast: for some movies, seeking is implemented by rewinding

• to the beginning and then fast-forwarding to the desired location. Even if

• the movie cannot seek, the seek method can still advance to an arbitrary

• location by reading samples and discarding them. However, to move

• backward, can_seek must return true.

*/

canSeekFast()

C++ Interface: can_seek_fast(MovieAudioCursor self)

/**

• Returns true if seek operations are constant time.

*/

can_seek()

C++ Interface: can_seek(MovieAudioCursor self)

/**

• Returns true if the movie can seek. If this is true, seeking is still not

• guaranteed to be fast: for some movies, seeking is implemented by rewinding

• to the beginning and then fast-forwarding to the desired location. Even if

• the movie cannot seek, the seek method can still advance to an arbitrary

• location by reading samples and discarding them. However, to move

• backward, can_seek must return true.

*/

can_seek_fast()

C++ Interface: can_seek_fast(MovieAudioCursor self)

/**

• Returns true if seek operations are constant time.

*/

getClassType()

C++ Interface: get_class_type()

getSource()

C++ Interface: get_source(MovieAudioCursor self)

/**

• Returns the MovieAudio which this cursor references.

*/

get_class_type()

C++ Interface: get_class_type()

get_source()

C++ Interface: get_source(MovieAudioCursor self)

/**

• Returns the MovieAudio which this cursor references.

*/

length()

C++ Interface: length(MovieAudioCursor self)

/**

• Returns the length of the movie. Attempting to read audio samples beyond

• the specified length will produce silent samples.

• Some kinds of Movie, such as internet TV station, might not have a

• predictable length. In that case, the length will be set to a very large

• number: 1.0E10.

• Some AVI files have incorrect length values encoded into them - they may be

• a second or two long or short. When playing such an AVI using the Movie

• class, you may see a slightly truncated video, or a slightly elongated

• video (padded with black frames). There are utilities out there to fix the

• length values in AVI files.

• An audio consumer needs to check the length, the ready status, and the

• aborted flag.

*/

readSamples()

C++ Interface: read_samples(const MovieAudioCursor self, int n) read_samples(const MovieAudioCursor self, int n, Datagram dg)

/**

• Read audio samples from the stream. N is the number of samples you wish to

• read. Your buffer must be equal in size to N * channels. Multiple-channel

• audio will be interleaved.

*/

/**

• Read audio samples from the stream into a Datagram. N is the number of

• samples you wish to read. Multiple-channel audio will be interleaved.

• This is not particularly efficient, but it may be a convenient way to

• manipulate samples in python.

*/

/**

• Read audio samples from the stream and returns them as a string. The

• samples are stored little-endian in the string. N is the number of samples

• you wish to read. Multiple-channel audio will be interleaved.

• This is not particularly efficient, but it may be a convenient way to

• manipulate samples in python.

*/

read_samples()

C++ Interface: read_samples(const MovieAudioCursor self, int n) read_samples(const MovieAudioCursor self, int n, Datagram dg)

/**

• Read audio samples from the stream. N is the number of samples you wish to

• read. Your buffer must be equal in size to N * channels. Multiple-channel

• audio will be interleaved.

*/

/**

• Read audio samples from the stream into a Datagram. N is the number of

• samples you wish to read. Multiple-channel audio will be interleaved.

• This is not particularly efficient, but it may be a convenient way to

• manipulate samples in python.

*/

/**

• Read audio samples from the stream and returns them as a string. The

• samples are stored little-endian in the string. N is the number of samples

• you wish to read. Multiple-channel audio will be interleaved.

• This is not particularly efficient, but it may be a convenient way to

• manipulate samples in python.

*/

ready()

C++ Interface: ready(MovieAudioCursor self)

/**

• Returns the number of audio samples that are ready to read. This is

• primarily relevant for sources like microphones which produce samples at a

• fixed rate. If you try to read more samples than are ready, the result

• will be silent samples.

• Some audio streams do not have a limit on how fast they can produce

• samples. Such streams will always return 0x40000000 as the ready-count.

• This may well exceed the length of the audio stream. You therefore need to

• check length separately.

• If the aborted flag is set, that means the ready count is no longer being

• replenished. For example, a MovieAudioCursor might be reading from an

• internet radio station, and it might buffer data to avoid underruns. If it

• loses connection to the radio station, it will set the aborted flag to

• indicate that the buffer is no longer being replenished. But it is still

• ok to read the samples that are in the buffer, at least until they run out.

• Once those are gone, there will be no more.

• An audio consumer needs to check the length, the ready status, and the

• aborted flag.

*/

seek()

C++ Interface: seek(const MovieAudioCursor self, double offset)

/**

• Skips to the specified offset within the file.

• If the movie reports that it cannot seek, then this method can still

• advance by reading samples and discarding them. However, to move backward,

• can_seek must be true.

• If the movie reports that it can_seek, it doesn’t mean that it can do so

• quickly. It may have to rewind the movie and then fast forward to the

• desired location. Only if can_seek_fast returns true can seek operations

• be done in constant time.

• Seeking may not be precise, because AVI files often have inaccurate

• indices. After seeking, tell will indicate that the cursor is at the

• target location. However, in truth, the data you read may come from a

• slightly offset location.

*/

skipSamples()

C++ Interface: skip_samples(const MovieAudioCursor self, int n)

/**

• Skip audio samples from the stream. This is mostly for debugging purposes.

*/

skip_samples()

C++ Interface: skip_samples(const MovieAudioCursor self, int n)

/**

• Skip audio samples from the stream. This is mostly for debugging purposes.

*/

tell()

C++ Interface: tell(MovieAudioCursor self)

/**

• Returns the current offset within the file.

*/