Filter SDK/VideoInfo

VideoInfo provides basic information about the clip your filter receives.

Getting information from VideoInfo

Video-related information

bool HasVideo();

This will return true if there is any video in the given clip.

bool IsRGB24();
bool IsRGB32();
bool IsRGB();

This will return true if the colorspace is RGB (in any way). The first two return true if the clip has the specific RGB colorspace (RGB24 and RGB32). The third returns true for any RGB colorspace; future formats could also apply.

bool IsYUY2();
bool IsYV12();
bool IsYUV();

This will return true if the colorspace is YUV (in any way). The first two return true if the clip has the specific YUV colorspace (YUY2 and YV12). The third returns true for any YUV colorspace; future formats could also apply. Note that I420 is also reported as YV12, because planes are automatically swapped.

bool IsColorSpace(int c_space);

This function will check if the colorspace (VideoInfo.pixel_type) is the same as given c_space (or more general it checks for a Colorspace property (see avisynth.h)).

bool IsSameColorspace(const VideoInfo& vi2);

This function will compare two VideoInfos, and check if the colorspace is the same. Note: It does not check imagesize or similar properties.

bool Is(int property);

This function is reserved for future use. Currently works as IsColorSpace.

bool IsPlanar();

This will return true if the video is planar. For now only YV12 returns true, but future formats might also do so. See the Planar image format.

bool IsFieldBased();

This will return true if the video has been through a SeparateFields, and the video has not been weaved yet. Otherwise it will return false.

bool IsParityKnown();

This will return true if the video parity is known.

bool IsBFF();
bool IsTFF();

This will return true if the video is bottom-field-first or top-field-first respectively.

 void SetFieldBased(bool isfieldbased);

This will set the field-based property to true (respectively false) if isfieldbased=true (respectively false).

 void Set(int property);
 void Clear(int property);

This sets respectively clears an image_type property like: IT_BFF, IT_TFF or IT_FIELDBASED. See field.h for examples.

 int BitsPerPixel();

This will return the number of bits per pixel. This can be:

pixel_type	nr of bits
CS_BGR24	24
CS_BGR32	32
CS_YUY2	16
CS_YV12, CS_I420	12

 void SetFPS(unsigned numerator, unsigned denominator);

This will set the framerate.

 void MulDivFPS(unsigned multiplier, unsigned divisor);

This will multiply the denominator by multiplier and scale the numerator and modified denominator.

There is some other useful information in VideoInfo structure (width, height, fps_numerator, fps_denominator, num_frames, pixel_type and image_type). See 'avisynth.h' header file.

Audio-related information

bool HasAudio();

This will return true if there is any audio in the given clip.

 int AudioChannels();

This will return the number of audio channels.

 int SampleType();

This will return the sampletype. This can be:

pixel_type	nr of bits
SAMPLE_INT8	1<<0
SAMPLE_INT16	1<<1
SAMPLE_INT24	1<<2
SAMPLE_INT32	1<<3
SAMPLE_FLOAT	1<<4

 bool IsSampleType(int testtype);

This function will check if the sampletype (VideoInfo.sample_type) is the same as testtype.

 int SamplesPerSecond();

This will return the number of bytes per second.

 int BytesPerAudioSample();

This will return the number of bytes per sample:

 int BytesPerChannelSample()

This will return the number of bytes per channel-sample. This can be:

sample	nr of bytes
SAMPLE_INT8	sizeof(signed char)
SAMPLE_INT16	sizeof(signed short)
SAMPLE_INT24	3
SAMPLE_INT32	sizeof(signed int)
SAMPLE_FLOAT	sizeof(SFLOAT)

 __int64 AudioSamplesFromFrames(__int64 frames);

This returns the number of audiosamples from the first frames frames.

 int FramesFromAudioSamples(__int64 samples);

This returns the number of frames from the first samples audiosamples.

 __int64 AudioSamplesFromBytes(__int64 bytes);

This returns the number of audiosamples from the first bytes bytes.

 __int64 BytesFromAudioSamples(__int64 samples);

This returns the number of bytes from the first samples audiosamples.

There is some other useful information in VideoInfo structure (audio_samples_per_second, sample_type, num_audio_samples and nchannels). See 'avisynth.h' header file.

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