View source for Filter SDK/Cplusplus API/VideoInfo

The VideoInfo structure holds global information about a clip (i.e. information that does not depend on the frame number). The GetVideoInfo method in IClip returns this structure. Below is a description of it (for AVISYNTH_INTERFACE_VERSION=6).

== Properties and constants ==

// General properties:
 int width, height;                       // width=0 means no video
 unsigned fps_numerator, fps_denominator;
 int num_frames;                          // max. num_frames = 2,147,483,647 (signed int32)
 int audio_samples_per_second;            // audio_samples_per_second=0 means no audio
 int sample_type;                         // samples types are defined in avisynth.h
 __int64 num_audio_samples;
 int nchannels;

// Colorspace properties and constants:
 int pixel_type; 
 
 enum {
   CS_BGR               = 1<<28,
   CS_YUV               = 1<<29,
   CS_INTERLEAVED       = 1<<30,
   CS_PLANAR            = 1<<31,
   
   // added in v5
   CS_Shift_Sub_Width   =  0,
   CS_Shift_Sub_Height  =  8,
   CS_Shift_Sample_Bits = 16,
   
   CS_Sub_Width_Mask    = 7 << CS_Shift_Sub_Width,
   CS_Sub_Width_1       = 3 << CS_Shift_Sub_Width, // YV24
   CS_Sub_Width_2       = 0 << CS_Shift_Sub_Width, // YV12, I420, YV16
   CS_Sub_Width_4       = 1 << CS_Shift_Sub_Width, // YUV9, YV411
   
   CS_VPlaneFirst       = 1 << 3, // YV12, YV16, YV24, YV411, YUV9
   CS_UPlaneFirst       = 1 << 4, // I420
   
   CS_Sub_Height_Mask   = 7 << CS_Shift_Sub_Height,
   CS_Sub_Height_1      = 3 << CS_Shift_Sub_Height, // YV16, YV24, YV411
   CS_Sub_Height_2      = 0 << CS_Shift_Sub_Height, // YV12, I420
   CS_Sub_Height_4      = 1 << CS_Shift_Sub_Height, // YUV9
   
   CS_Sample_Bits_Mask  = 7 << CS_Shift_Sample_Bits,
   CS_Sample_Bits_8     = 0 << CS_Shift_Sample_Bits,
   CS_Sample_Bits_16    = 1 << CS_Shift_Sample_Bits,
   CS_Sample_Bits_32    = 2 << CS_Shift_Sample_Bits,
   
   CS_PLANAR_MASK       = CS_PLANAR | CS_INTERLEAVED | CS_YUV | CS_BGR | CS_Sample_Bits_Mask | CS_Sub_Height_Mask | CS_Sub_Width_Mask,
   CS_PLANAR_FILTER     = ~( CS_VPlaneFirst | CS_UPlaneFirst ),
 };

// Colorformat constants:

 enum {
   CS_UNKNOWN = 0,
   CS_BGR24 = 1<<0 | CS_BGR | CS_INTERLEAVED,
   CS_BGR32 = 1<<1 | CS_BGR | CS_INTERLEAVED,
   CS_YUY2  = 1<<2 | CS_YUV | CS_INTERLEAVED,
   CS_YV12  = 1<<3 | CS_YUV | CS_PLANAR,  // y-v-u, 4:2:0 planar // only in v3
   CS_I420  = 1<<4 | CS_YUV | CS_PLANAR,  // y-u-v, 4:2:0 planar // only in v3
   CS_IYUV  = 1<<4 | CS_YUV | CS_PLANAR,  // same as above // only in v3
   
   // added in v5
   CS_RAW32 = 1<<5 | CS_INTERLEAVED,
   CS_YV24  = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_VPlaneFirst | CS_Sub_Height_1 | CS_Sub_Width_1,  // YUV 4:4:4 planar
   CS_YV16  = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_VPlaneFirst | CS_Sub_Height_1 | CS_Sub_Width_2,  // YUV 4:2:2 planar
   CS_YV12  = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_VPlaneFirst | CS_Sub_Height_2 | CS_Sub_Width_2,  // y-v-u, 4:2:0 planar
   CS_I420  = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_UPlaneFirst | CS_Sub_Height_2 | CS_Sub_Width_2,  // y-u-v, 4:2:0 planar
   CS_IYUV  = CS_I420,
   CS_YUV9  = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_VPlaneFirst | CS_Sub_Height_4 | CS_Sub_Width_4,  // YUV 4:1:0 planar
   CS_YV411 = CS_PLANAR | CS_YUV | CS_Sample_Bits_8 | CS_VPlaneFirst | CS_Sub_Height_1 | CS_Sub_Width_4,  // YUV 4:1:1 planar
   
   CS_Y8    = CS_PLANAR | CS_INTERLEAVED | CS_YUV | CS_Sample_Bits_8,                                     // Y   4:0:0 planar
 };

// Image_type properties and constants:
 int image_type;
 
 enum {
   IT_BFF        = 1<<0,
   IT_TFF        = 1<<1,
   IT_FIELDBASED = 1<<2
 };

// Chroma placement constants (bits 20 -> 23):

 enum { // added in v5
   CS_UNKNOWN_CHROMA_PLACEMENT = 0 << 20,
   CS_MPEG1_CHROMA_PLACEMENT   = 1 << 20,
   CS_MPEG2_CHROMA_PLACEMENT   = 2 << 20,
   CS_YUY2_CHROMA_PLACEMENT    = 3 << 20,
   CS_TOPLEFT_CHROMA_PLACEMENT = 4 << 20
 };

== Functions [need to add examples] ==

=== HasVideo ===

 bool HasVideo() const;

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

=== IsRGB / IsRGB24 / IsRGB32 ===

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

All of them will return true if the colorspace is [[RGB]] (in any way). The last two return true if the clip has the specific RGB colorspace ([[RGB24]] and [[RGB32]]).

=== IsYUV / IsYUY2 / IsYV24 / IsYV16 / IsYV12 / IsYV411 / IsY8 ===

 bool IsYUV() const;
 bool IsYUY2() const;
 bool IsYV24() const;   // v5
 bool IsYV16() const;   // v5
 bool IsYV12() const;
 bool IsYV411() const;  // v5
 bool IsY8() const;     // v5

All of them will return true if the colorspace is [[YUV]] (in any way). The last six return true if the clip has the specific YUV colorspace ([[YUY2]], [[YV24]], [[YV16]], [[YV12]], [[YV411]] and [[Y8]]).

=== IsColorSpace / IsSameColorspace / IsPlanar ===

 bool IsColorSpace(int c_space) const;

This will return true if the colorspace (VideoInfo.pixel_type) is the same as the given c_space (or more general it checks for a [[Colorspace property]]).

 bool IsSameColorspace(const VideoInfo& vi) const;

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

 bool IsPlanar() const;

This will return true if the video is planar. See the [[Planar]] image format.

=== Is / IsFieldBased / IsParityKnown / IsBFF / IsTFF ===

 bool Is(int property) const;

From v6 this will return true if the image type (VideoInfo.image_type) is the same as the given property (being IT_BFF, IT_TFF or IT_FIELDBASED).

 bool IsFieldBased() const;

This will return true if the video is field-based. Thus if has been through a [[SeparateFields]] or [[AssumeFieldBased]]. Otherwise it will return false.

 bool IsParityKnown() const;

This will return true if the video parity is known (thus if it is TFF or BFF).

 bool IsBFF() const;
 bool IsTFF() const;

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

=== SetFieldBased / Set / Clear ===

 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.

=== BitsPerPixel ===

 int BitsPerPixel() const;

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

{| border="1" cellpadding="4"
!width=50%| pixel_type
!width=50%| nr of bits
|-
| CS_BGR32
| 32
|-
| CS_BGR24, CS_YV24
| 24
|-
| CS_YUY2, CS_YV16
| 16
|-
| CS_YV12, CS_I420
| 12
|-
| CS_Y8
| 8
|-
| CS_YV411
| 6
|}
Do not mismatch with {{AvsPluscon}} BitsPerComponent Avisynth+ function

=== SetFPS / MulDivFPS ===

 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.

=== BytesFromPixels ===

 int BytesFromPixels(int pixels) const;

For interleaved formats it will return the number of bytes from the specified number of pixels. For planar formats it will do the same except it operates on the first plane.

=== RowSize / BMPSize ===

 int RowSize(int plane=0) const;

For interleaved formats it will return the width of the frame in bytes. For planar formats it will return the width of the specified plane in bytes.

examples:

640x480 RGB24:  RowSize() = 3*640 = 1920

640x480 YV12: RowSize() = 640 <br>
640x480 YV12: RowSize(1) = 320

 int BMPSize() const;

For interleaved formats it will return the size of the frame in bytes where the width is rounded up to a multiple of 4 bytes. For planar formats it will do the same but only for the first plane. So, it's the number of bytes of a frame as it was a [http://en.wikipedia.org/wiki/BMP_file_format BMP frame].

examples:

640x480 RGB24: BMPSize() = 480 * 3*640 = 921600 <br>
643x480 RGB24: BMPSize() = 480 * 3*644 = 927360

640x480 YV24: BMPSize() = 480 * 640 = 307200 <br>
643x480 YV24: BMPSize() = 480 * 644 = 309120

Since v5 the behavior for planar formats is the same as for interleaved formats.

=== GetPlaneWidthSubsampling / GetPlaneHeightSubsampling ===

 int GetPlaneWidthSubsampling(int plane) const; // v5

This will return the subsampling of the width in bitshifts.

examples:

YV24: GetPlaneWidthSubsampling(PLANAR_U) = 0 // since there is no horizontal subsampling on a chroma plane <br>
YV16: GetPlaneWidthSubsampling(PLANAR_U) = 1 // since chroma horizontal resolution is halved<br>
YV12: GetPlaneWidthSubsampling(PLANAR_U) = 1 // since chroma horizontal resolution is halved

 int GetPlaneHeightSubsampling(int plane) const; // v5

This will return the subsampling of the height in bitshifts.

examples:

YV24: GetPlaneHeightSubsampling(PLANAR_U) = 0 // since there is no vertical subsampling on a chroma plane <br>
YV16: GetPlaneHeightSubsampling(PLANAR_U) = 0 // no vertical subsampling either<br>
YV12: GetPlaneHeightSubsampling(PLANAR_U) = 1 // since vertically there are two times less samples on a chroma plane compared to a plane which is not subsampled

{| border="1"
|- 
| color format
| GetPlaneWidthSubsampling(PLANAR_U)
| GetPlaneHeightSubsampling(PLANAR_U)
|- 
| YV24 (4:4:4)
| 0
| 0
|- 
| YV16 (4:2:2)
| 1
| 0
|- 
| YV12 (4:2:0)
| 1
| 1
|- 
| YV411 (4:1:1)
| 2
| 0
|- 
| Y8
| 0 ?
| 0 ?
|}

=== HasAudio ===

 bool HasAudio() const;

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

=== AudioChannels / SampleType ===

 int AudioChannels() const;

This will return the number of audio channels.

 int SampleType() const;

This will return the sample type. See [[Filter_SDK/Cplusplus_API#Constants|constants]] for the available sample types.

=== IsSampleType ===

 bool IsSampleType(int testtype) const;

This will return true if the sampletype (VideoInfo.sample_type) is the same as testtype.

=== SamplesPerSecond / BytesPerAudioSample / BytesPerChannelSample ===

 int SamplesPerSecond() const;

This will return the number of samples per second.

 int BytesPerAudioSample() const;

This will return the number of bytes per sample.

 int BytesPerChannelSample() const;

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

{| border="1" cellpadding="4"
!width=50%| sample
!width=50%| 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)
|}

=== AudioSamplesFromFrames / FramesFromAudioSamples / AudioSamplesFromBytes / BytesFromAudioSamples ===

 __int64 AudioSamplesFromFrames(int frames) const;

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

 int FramesFromAudioSamples(__int64 samples) const;

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

 __int64 AudioSamplesFromBytes(__int64 bytes) const;

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

 __int64 BytesFromAudioSamples(__int64 samples) const;

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

[[Category:AviSynth_Development]]