INFO=GETINFO(VR)
Returns a structure whose fields contain information about the opened
video object. The (minimum) set of fields in the INFO structure is
shown below:
url String specifying the data source, in the format preferred
by the plugin being used. Sometimes this will be a true
URL, sometimes it will be a filename.
fps Non-negative number indicating the number of frames per
second.
height Integer indicating the height of the video frames in
pixels.
width Integer indicating the width of the video frames in pixels.
numFrames Integer indicating an estimate of the total number of
frames in the video. For typical videos, this number is
exact. Users may attempt to read more than numFrames
frames at their own risk. If nHiddenFinalFrames is
non-zero, this will typically fail (meaning next/step/seek
will return 0) or worse, corrupted data such as an
all-black frame may be returned by the codec. Some plugins
and/or their codecs do not supply this information. If the
number of frames is unknown, a negative number is returned.
Older ffmpeg versions (notably version 0.4.9-pre1) do not
supply this number.
fourcc 4- or fewer-character string roughly indicating the codec
used encode the video. See http://www.fourcc.org for
additional background information and an extensive, but
non-comprehensive list of FourCC codes.
nHiddenFinalFrames
Non-negative integer. Many codecs make it difficult or
impossible to read the last few frames of a file. When
videoReader thinks that the last few cannot be read, it
automatically guesses how many frames cannot be read,
records this number as nHiddenFinalFrames, and sets
numFrames to be the number of frames the file claims to
contain minus nHiddenFinalFrames. An individual
videoReader plugin (like the ffmpegPopen2 plugin) may choose
to allow the user to try reading the frames that might be
hidden or it may choose not to allow even trying to read
them (like the DirectShow plugin).
Due to limitations in some file formats, it is not always possible to
determine all of these values (or sometimes they are not constant). In
these cases, numerical values are given a value of NaN and string values
are blank.
SEE ALSO
videoReader
Copyright (c) 2006 Gerald Dalley
See "MIT.txt" in the installation directory for licensing details (especially
when using this library on GNU/Linux).0001 function info = getinfo(vr) 0002 %INFO=GETINFO(VR) 0003 % Returns a structure whose fields contain information about the opened 0004 % video object. The (minimum) set of fields in the INFO structure is 0005 % shown below: 0006 % url String specifying the data source, in the format preferred 0007 % by the plugin being used. Sometimes this will be a true 0008 % URL, sometimes it will be a filename. 0009 % 0010 % fps Non-negative number indicating the number of frames per 0011 % second. 0012 % 0013 % height Integer indicating the height of the video frames in 0014 % pixels. 0015 % 0016 % width Integer indicating the width of the video frames in pixels. 0017 % 0018 % numFrames Integer indicating an estimate of the total number of 0019 % frames in the video. For typical videos, this number is 0020 % exact. Users may attempt to read more than numFrames 0021 % frames at their own risk. If nHiddenFinalFrames is 0022 % non-zero, this will typically fail (meaning next/step/seek 0023 % will return 0) or worse, corrupted data such as an 0024 % all-black frame may be returned by the codec. Some plugins 0025 % and/or their codecs do not supply this information. If the 0026 % number of frames is unknown, a negative number is returned. 0027 % Older ffmpeg versions (notably version 0.4.9-pre1) do not 0028 % supply this number. 0029 % 0030 % fourcc 4- or fewer-character string roughly indicating the codec 0031 % used encode the video. See http://www.fourcc.org for 0032 % additional background information and an extensive, but 0033 % non-comprehensive list of FourCC codes. 0034 % 0035 % nHiddenFinalFrames 0036 % Non-negative integer. Many codecs make it difficult or 0037 % impossible to read the last few frames of a file. When 0038 % videoReader thinks that the last few cannot be read, it 0039 % automatically guesses how many frames cannot be read, 0040 % records this number as nHiddenFinalFrames, and sets 0041 % numFrames to be the number of frames the file claims to 0042 % contain minus nHiddenFinalFrames. An individual 0043 % videoReader plugin (like the ffmpegPopen2 plugin) may choose 0044 % to allow the user to try reading the frames that might be 0045 % hidden or it may choose not to allow even trying to read 0046 % them (like the DirectShow plugin). 0047 % 0048 % Due to limitations in some file formats, it is not always possible to 0049 % determine all of these values (or sometimes they are not constant). In 0050 % these cases, numerical values are given a value of NaN and string values 0051 % are blank. 0052 % 0053 %SEE ALSO 0054 % videoReader 0055 % 0056 %Copyright (c) 2006 Gerald Dalley 0057 %See "MIT.txt" in the installation directory for licensing details (especially 0058 %when using this library on GNU/Linux). 0059 0060 %info = feval(vr.plugin, 'getinfo', vr.handle); 0061 0062 [names, vals] = feval(vr.plugin, 'getinfo', vr.handle); 0063 info = cell2struct({vals{:}}, {names{:}}, 2);