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MovieVideoCursor Class Reference

A MovieVideo is actually any source that provides a sequence of video frames. More...

#include "movieVideoCursor.h"

Inheritance diagram for MovieVideoCursor:
TypedWritableReferenceCount TypedWritable ReferenceCount TypedObject MemoryBase MemoryBase InkblotVideoCursor

List of all members.

Classes

class  Buffer

Public Member Functions

bool aborted () const
 Returns true if the video has aborted prematurely.
virtual void apply_to_texture (const Buffer *buffer, Texture *t, int page)
 Stores this buffer's contents in the indicated texture.
virtual void apply_to_texture_alpha (const Buffer *buffer, Texture *t, int page, int alpha_src)
 Copies this buffer's contents into the alpha channel of the supplied texture.
virtual void apply_to_texture_rgb (const Buffer *buffer, Texture *t, int page)
 Copies this buffer's contents into the RGB channels of the supplied texture.
bool can_seek () const
 Returns true if the movie can seek.
bool can_seek_fast () const
 Returns true if seek operations are constant time.
virtual int complete_pointers (TypedWritable **plist, BamReader *manager)
 Receives an array of pointers, one for each time manager->read_pointer() was called in fillin().
virtual TypeHandle force_init_type ()
int get_num_components () const
 Returns 4 if the movie has an alpha channel, 3 otherwise.
virtual TypeHandle get_type () const
double length () const
 Returns the length of the movie.
virtual PT (Buffer) fetch_buffer()
 PT (MovieVideo) get_source() const
bool ready () const
 Returns true if the cursor is a streaming source, and if a video frame is ready to be read.
virtual bool set_time (double timestamp, int loop_count)
 Updates the cursor to the indicated time.
void setup_texture (Texture *tex) const
 Set up the specified Texture object to contain content from this movie.
int size_x () const
 Get the horizontal size of the movie.
int size_y () const
 Get the vertical size of the movie.
bool streaming () const
 Returns true if the video frames are being "pushed" at us by something that operates at its own speed - for example, a webcam.
virtual void write_datagram (BamWriter *manager, Datagram &dg)
 Writes the contents of this object to the datagram for shipping out to a Bam file.

Static Public Member Functions

static TypeHandle get_class_type ()
static void init_type ()

Protected Member Functions

 MovieVideoCursor (MovieVideo *src=NULL)
 This is a virtual base class and should not be created directly.
void fillin (DatagramIterator &scan, BamReader *manager)
 This internal function is called by make_from_bam to read in all of the relevant data from the BamFile for the new MovieVideoCursor.
Bufferget_standard_buffer ()
 May be called by a derived class to return a single standard Buffer object to easily implement fetch_buffer().
 PT (MovieVideo) _source
virtual PT (Buffer) make_new_buffer()
 PT (Buffer) _standard_buffer

Protected Attributes

bool _aborted
bool _can_seek
bool _can_seek_fast
double _length
int _num_components
bool _ready
int _size_x
int _size_y
bool _streaming

Static Protected Attributes

static PStatCollector _copy_pcollector
static PStatCollector _copy_pcollector_copy
static PStatCollector _copy_pcollector_ram

Detailed Description

A MovieVideo is actually any source that provides a sequence of video frames.

That could include an AVI file, a digital camera, or an internet TV station. A MovieVideoCursor is a handle that lets you read data sequentially from a MovieVideo.

Thread safety: each individual MovieVideoCursor 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 MovieVideoCursor objects.

Definition at line 45 of file movieVideoCursor.h.


Constructor & Destructor Documentation

MovieVideoCursor::MovieVideoCursor ( MovieVideo src = NULL) [protected]

This is a virtual base class and should not be created directly.

Instead, create a more specialized class.

Definition at line 37 of file movieVideoCursor.cxx.


Member Function Documentation

bool MovieVideoCursor::aborted ( ) const [inline]

Returns true if the video has aborted prematurely.

For example, this could occur if the Movie was actually an internet TV station, and the connection was lost. Reaching the normal end of the video does not constitute an 'abort' condition.

Definition at line 129 of file movieVideoCursor.I.

void MovieVideoCursor::apply_to_texture ( const Buffer buffer,
Texture t,
int  page 
) [virtual]
void MovieVideoCursor::apply_to_texture_alpha ( const Buffer buffer,
Texture t,
int  page,
int  alpha_src 
) [virtual]

Copies this buffer's contents into the alpha channel of the supplied texture.

The RGB channels of the texture are not touched.

Definition at line 190 of file movieVideoCursor.cxx.

References Texture::get_component_width(), Texture::get_expected_ram_page_size(), get_num_components(), Texture::get_num_components(), Texture::get_x_size(), Texture::get_y_size(), Texture::modify_ram_image(), Texture::set_keep_ram_image(), size_x(), and size_y().

void MovieVideoCursor::apply_to_texture_rgb ( const Buffer buffer,
Texture t,
int  page 
) [virtual]

Copies this buffer's contents into the RGB channels of the supplied texture.

The alpha channel of the texture is not touched.

Definition at line 247 of file movieVideoCursor.cxx.

References Texture::get_component_width(), Texture::get_expected_ram_page_size(), get_num_components(), Texture::get_num_components(), Texture::get_x_size(), Texture::get_y_size(), Texture::modify_ram_image(), Texture::set_keep_ram_image(), size_x(), and size_y().

bool MovieVideoCursor::can_seek ( ) const [inline]

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 fetch methods can still advance to an arbitrary location by reading frames and discarding them. However, to move backward, can_seek must return true.

Definition at line 105 of file movieVideoCursor.I.

bool MovieVideoCursor::can_seek_fast ( ) const [inline]

Returns true if seek operations are constant time.

Definition at line 115 of file movieVideoCursor.I.

int MovieVideoCursor::complete_pointers ( TypedWritable **  p_list,
BamReader manager 
) [virtual]

Receives an array of pointers, one for each time manager->read_pointer() was called in fillin().

Returns the number of pointers processed.

Reimplemented from TypedWritable.

Definition at line 332 of file movieVideoCursor.cxx.

void MovieVideoCursor::fillin ( DatagramIterator scan,
BamReader manager 
) [protected, virtual]

This internal function is called by make_from_bam to read in all of the relevant data from the BamFile for the new MovieVideoCursor.

Reimplemented from TypedWritable.

Definition at line 348 of file movieVideoCursor.cxx.

References BamReader::read_pointer().

int MovieVideoCursor::get_num_components ( ) const [inline]

Returns 4 if the movie has an alpha channel, 3 otherwise.

Definition at line 52 of file movieVideoCursor.I.

Referenced by apply_to_texture(), apply_to_texture_alpha(), apply_to_texture_rgb(), and setup_texture().

MovieVideoCursor::Buffer * MovieVideoCursor::get_standard_buffer ( ) [protected]

May be called by a derived class to return a single standard Buffer object to easily implement fetch_buffer().

Definition at line 293 of file movieVideoCursor.cxx.

double MovieVideoCursor::length ( ) const [inline]

Returns the length of the movie.

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. If the internet TV station goes offline, the video or audio stream will set its abort flag. Reaching the end of the movie (ie, the specified length) normally does not cause the abort flag to be set.

The video and audio streams produced by get_video and get_audio are always of unlimited duration - you can always read another video frame or another audio sample. This is true even if the specified length is reached, or an abort is flagged. If either stream runs out of data, it will synthesize blank video frames and silent audio samples as necessary to satisfy read requests.

Some AVI files have incorrect length values encoded into them - usually, they're 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.

Definition at line 88 of file movieVideoCursor.I.

bool MovieVideoCursor::ready ( ) const [inline]

Returns true if the cursor is a streaming source, and if a video frame is ready to be read.

For non- streaming sources, this is always false.

Definition at line 162 of file movieVideoCursor.I.

bool MovieVideoCursor::set_time ( double  timestamp,
int  loop_count 
) [virtual]

Updates the cursor to the indicated time.

If loop_count >= 1, the time is clamped to the movie's length * loop_count. If loop_count <= 0, the time is understood to be modulo the movie's length.

Returns true if a new frame is now available, false otherwise. If this returns true, you should immediately follow this with exactly *one* call to fetch_buffer().

If the movie reports that it can_seek, you may also specify a time value less than the previous value you passed to set_time(). Otherwise, you may only specify a time value greater than or equal to the previous value.

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 it seek rapidly.

Reimplemented in InkblotVideoCursor.

Definition at line 103 of file movieVideoCursor.cxx.

void MovieVideoCursor::setup_texture ( Texture tex) const

Set up the specified Texture object to contain content from this movie.

This should be called once, not every frame.

Definition at line 68 of file movieVideoCursor.cxx.

References Texture::adjust_this_size(), get_num_components(), Texture::set_pad_size(), Texture::setup_texture(), size_x(), and size_y().

int MovieVideoCursor::size_x ( ) const [inline]

Get the horizontal size of the movie.

Definition at line 31 of file movieVideoCursor.I.

Referenced by apply_to_texture(), apply_to_texture_alpha(), apply_to_texture_rgb(), and setup_texture().

int MovieVideoCursor::size_y ( ) const [inline]

Get the vertical size of the movie.

Definition at line 41 of file movieVideoCursor.I.

Referenced by apply_to_texture(), apply_to_texture_alpha(), apply_to_texture_rgb(), and setup_texture().

bool MovieVideoCursor::streaming ( ) const [inline]

Returns true if the video frames are being "pushed" at us by something that operates at its own speed - for example, a webcam.

In this case, the frames come when they're ready to come. Attempting to read too soon will produce nothing, reading too late will cause frames to be dropped. In this case, the ready flag can be used to determine whether or not a frame is ready for reading.

When streaming, you should still pay attention to last_start, but the value of next_start is only a guess.

Definition at line 150 of file movieVideoCursor.I.

void MovieVideoCursor::write_datagram ( BamWriter manager,
Datagram dg 
) [virtual]

Writes the contents of this object to the datagram for shipping out to a Bam file.

Reimplemented from TypedWritable.

Definition at line 318 of file movieVideoCursor.cxx.

References BamWriter::write_pointer().


The documentation for this class was generated from the following files:
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