Image codecs

IMREAD_UNCHANGED: If set, return the loaded image as is (with alpha channel, otherwise it gets cropped). Ignore EXIF orientation.
IMREAD_GRAYSCALE: If set, always convert image to the single channel grayscale image (codec internal conversion).
IMREAD_COLOR_BGR: Same as IMREAD_COLOR_BGR.
IMREAD_COLOR: Same as IMREAD_COLOR_BGR.
IMREAD_ANYDEPTH: If set, return 16-bit/32-bit image when the input has the corresponding depth, otherwise convert it to 8-bit.
IMREAD_ANYCOLOR: If set, the image is read in any possible color format.
IMREAD_LOAD_GDAL: If set, use the gdal driver for loading the image.
IMREAD_REDUCED_GRAYSCALE_2: If set, always convert image to the single channel grayscale image and the image size reduced 1/2.
IMREAD_REDUCED_COLOR_2: If set, always convert image to the 3 channel BGR color image and the image size reduced 1/2.
IMREAD_REDUCED_GRAYSCALE_4: If set, always convert image to the single channel grayscale image and the image size reduced 1/4.
IMREAD_REDUCED_COLOR_4: If set, always convert image to the 3 channel BGR color image and the image size reduced 1/4.
IMREAD_REDUCED_GRAYSCALE_8: If set, always convert image to the single channel grayscale image and the image size reduced 1/8.
IMREAD_REDUCED_COLOR_8: If set, always convert image to the 3 channel BGR color image and the image size reduced 1/8.
IMREAD_IGNORE_ORIENTATION: If set, do not rotate the image according to EXIF's orientation flag.
IMREAD_COLOR_RGB: If set, always convert image to the 3 channel RGB color image.
IMWRITE_JPEG_QUALITY: For JPEG, it can be a quality from 0 to 100 (the higher is the better). Default value is 95.
IMWRITE_JPEG_PROGRESSIVE: Enable JPEG features, 0 or 1, default is False.
IMWRITE_JPEG_OPTIMIZE: Enable JPEG features, 0 or 1, default is False.
IMWRITE_JPEG_RST_INTERVAL: JPEG restart interval, 0 - 65535, default is 0 - no restart.
IMWRITE_JPEG_LUMA_QUALITY: Separate luma quality level, 0 - 100, default is -1 - don't use. If JPEG_LIB_VERSION < 70, Not supported.
IMWRITE_JPEG_CHROMA_QUALITY: Separate chroma quality level, 0 - 100, default is -1 - don't use. If JPEG_LIB_VERSION < 70, Not supported.
IMWRITE_JPEG_SAMPLING_FACTOR: For JPEG, set sampling factor. See cv::ImwriteJPEGSamplingFactorParams.
IMWRITE_PNG_COMPRESSION: For PNG, it can be the compression level from 0 to 9. A higher value means a smaller size and longer compression time. If specified, strategy is changed to IMWRITE_PNG_STRATEGY_DEFAULT (Z_DEFAULT_STRATEGY). Default value is 1 (best speed setting).
IMWRITE_PNG_STRATEGY: For PNG, One of cv::ImwritePNGFlags, default is IMWRITE_PNG_STRATEGY_RLE.
IMWRITE_PNG_BILEVEL: For PNG, Binary level PNG, 0 or 1, default is 0. For APNG, it is not supported.
IMWRITE_PNG_FILTER: For PNG, One of cv::ImwritePNGFilterFlags, default is IMWRITE_PNG_FILTER_SUB. For APNG, it is not supported.
IMWRITE_PNG_ZLIBBUFFER_SIZE: For PNG with libpng, sets the size of the internal zlib compression buffer in bytes, from 6 to 1048576(1024 KiB). Default is 8192(8 KiB). For normal use, 131072(128 KiB) or 262144(256 KiB) may be sufficient. If WITH_SPNG=ON, it is not supported. For APNG, it is not supported.
IMWRITE_PXM_BINARY: For PPM, PGM, or PBM, it can be a binary format flag, 0 or 1. Default value is 1.
IMWRITE_EXR_TYPE: 48 * /, //!< override EXR storage type (FLOAT (FP32) is default)
IMWRITE_EXR_COMPRESSION: 49 * /, //!< override EXR compression type (ZIP_COMPRESSION = 3 is default)
IMWRITE_EXR_DWA_COMPRESSION_LEVEL: 50 * /, //!< override EXR DWA compression level (45 is default)
IMWRITE_WEBP_QUALITY: For WEBP, it can be a lossy quality from 1 to 100 (the higher is the better) for IMWRITE_WEBP_LOSSLESS_OFF. By default (without this parameter) or if quality > 100, IMWRITE_WEBP_LOSSLESS_ON is used instead.
IMWRITE_WEBP_LOSSLESS_MODE: For WEBP, it can be a lossless compression strategy. See cv::ImwriteWEBPLosslessMode. Default is IMWRITE_WEBP_LOSSLESS_OFF. For Animated WEBP, it is not supported.
IMWRITE_HDR_COMPRESSION: 80 * /, //!< specify HDR compression
IMWRITE_PAM_TUPLETYPE: For PAM, sets the TUPLETYPE field to the corresponding string value that is defined for the format
IMWRITE_TIFF_RESUNIT: For TIFF, use to specify which DPI resolution unit to set. See ImwriteTiffResolutionUnitFlags. Default is IMWRITE_TIFF_RESOLUTION_UNIT_INCH.
IMWRITE_TIFF_XDPI: For TIFF, use to specify the X direction DPI
IMWRITE_TIFF_YDPI: For TIFF, use to specify the Y direction DPI
IMWRITE_TIFF_COMPRESSION: For TIFF, use to specify the image compression scheme. See cv::ImwriteTiffCompressionFlags. The compression scheme can be specified by this flag; the default is LZW compression, except for 32F depth where it is NONE
IMWRITE_TIFF_ROWSPERSTRIP: For TIFF, use to specify the number of rows per strip.
IMWRITE_TIFF_PREDICTOR: For TIFF, use to specify predictor. See cv::ImwriteTiffPredictorFlags. Default is IMWRITE_TIFF_PREDICTOR_HORIZONTAL .
IMWRITE_JPEG2000_COMPRESSION_X1000: For JPEG2000, use to specify the target compression rate (multiplied by 1000). The value can be from 0 to 1000. Default is 1000.
IMWRITE_AVIF_QUALITY: For AVIF, it can be a quality between 0 and 100 (the higher the better). Default is 95.
IMWRITE_AVIF_DEPTH: For AVIF, it can be 8, 10 or 12. If >8, it is stored/read as CV_16U. Default is 8.
IMWRITE_AVIF_SPEED: For AVIF, it is between 0 (slowest) and 10(fastest). Default is 9.
IMWRITE_JPEGXL_QUALITY: For JPEG XL, it can be a quality from 0 to 100 (the higher is the better). Default value is 95. If set, distance parameter is re-calicurated from quality level automatically. This parameter request libjxl v0.10 or later.
IMWRITE_JPEGXL_EFFORT: For JPEG XL, encoder effort/speed level without affecting decoding speed; it is between 1 (fastest) and 10 (slowest). Default is 7.
IMWRITE_JPEGXL_DISTANCE: For JPEG XL, distance level for lossy compression: target max butteraugli distance, lower = higher quality, 0 = lossless; range: 0 .. 25. Default is 1.
IMWRITE_JPEGXL_DECODING_SPEED: For JPEG XL, decoding speed tier for the provided options; minimum is 0 (slowest to decode, best quality/density), and maximum is 4 (fastest to decode, at the cost of some quality/density). Default is 0.
IMWRITE_BMP_COMPRESSION: For BMP, use to specify compress parameter for 32bpp image. Default is IMWRITE_BMP_COMPRESSION_BITFIELDS. See cv::ImwriteBMPCompressionFlags.
IMWRITE_GIF_LOOP: Not functional since 4.12.0. Replaced by cv::Animation::loop_count.
IMWRITE_GIF_SPEED: Not functional since 4.12.0. Replaced by cv::Animation::durations.
IMWRITE_GIF_QUALITY: For GIF, it can be a quality from 1 to 8. Default is 2. See cv::ImwriteGifCompressionFlags.
IMWRITE_GIF_DITHER: For GIF, it can be a quality from -1(most dither) to 3(no dither). Default is 0.
IMWRITE_GIF_TRANSPARENCY: For GIF, the alpha channel lower than this will be set to transparent. Default is 1.
IMWRITE_GIF_COLORTABLE: For GIF, 0 means global color table is used, 1 means local color table is used. Default is 0.
IMWRITE_JPEG_SAMPLING_FACTOR_411: IMWRITE_JPEG_SAMPLING_FACTOR_411: 4x1,1x1,1x1
IMWRITE_JPEG_SAMPLING_FACTOR_420: 2x2,1x1,1x1(Default)
IMWRITE_JPEG_SAMPLING_FACTOR_422: IMWRITE_JPEG_SAMPLING_FACTOR_422: 2x1,1x1,1x1
IMWRITE_JPEG_SAMPLING_FACTOR_440: IMWRITE_JPEG_SAMPLING_FACTOR_440: 1x2,1x1,1x1
IMWRITE_JPEG_SAMPLING_FACTOR_444: 1x1,1x1,1x1(No subsampling)
IMWRITE_TIFF_COMPRESSION_NONE: IMWRITE_TIFF_COMPRESSION_NONE: dump mode
IMWRITE_TIFF_COMPRESSION_CCITTRLE: CCITT modified Huffman RLE
IMWRITE_TIFF_COMPRESSION_CCITTFAX3: CCITT Group 3 fax encoding
IMWRITE_TIFF_COMPRESSION_CCITT_T4: CCITT T.4 (TIFF 6 name)
IMWRITE_TIFF_COMPRESSION_CCITTFAX4: CCITT Group 4 fax encoding
IMWRITE_TIFF_COMPRESSION_CCITT_T6: CCITT T.6 (TIFF 6 name)
IMWRITE_TIFF_COMPRESSION_LZW: Lempel-Ziv & Welch
IMWRITE_TIFF_COMPRESSION_OJPEG: IMWRITE_TIFF_COMPRESSION_OJPEG: !6.0 JPEG
IMWRITE_TIFF_COMPRESSION_JPEG: %JPEG DCT compression
IMWRITE_TIFF_COMPRESSION_T85: !TIFF/FX T.85 JBIG compression
IMWRITE_TIFF_COMPRESSION_T43: !TIFF/FX T.43 colour by layered JBIG compression
IMWRITE_TIFF_COMPRESSION_NEXT: IMWRITE_TIFF_COMPRESSION_NEXT: NeXT 2-bit RLE
IMWRITE_TIFF_COMPRESSION_CCITTRLEW: #1 w/ word alignment
IMWRITE_TIFF_COMPRESSION_PACKBITS: IMWRITE_TIFF_COMPRESSION_PACKBITS: Macintosh RLE
IMWRITE_TIFF_COMPRESSION_THUNDERSCAN: ThunderScan RLE
IMWRITE_TIFF_COMPRESSION_IT8CTPAD: IT8 CT w/padding
IMWRITE_TIFF_COMPRESSION_IT8LW: IT8 Linework RLE
IMWRITE_TIFF_COMPRESSION_IT8MP: IT8 Monochrome picture
IMWRITE_TIFF_COMPRESSION_IT8BL: IT8 Binary line art
IMWRITE_TIFF_COMPRESSION_PIXARFILM: Pixar companded 10bit LZW
IMWRITE_TIFF_COMPRESSION_PIXARLOG: Pixar companded 11bit ZIP
IMWRITE_TIFF_COMPRESSION_DEFLATE: Deflate compression, legacy tag
IMWRITE_TIFF_COMPRESSION_ADOBE_DEFLATE: Deflate compression, as recognized by Adobe
IMWRITE_TIFF_COMPRESSION_DCS: Kodak DCS encoding
IMWRITE_TIFF_COMPRESSION_JBIG: IMWRITE_TIFF_COMPRESSION_JBIG: ISO JBIG
IMWRITE_TIFF_COMPRESSION_SGILOG: SGI Log Luminance RLE
IMWRITE_TIFF_COMPRESSION_SGILOG24: SGI Log 24-bit packed
IMWRITE_TIFF_COMPRESSION_JP2000: Leadtools JPEG2000
IMWRITE_TIFF_COMPRESSION_LERC: ESRI Lerc codec: https://github.com/Esri/lerc
IMWRITE_TIFF_COMPRESSION_LZMA: IMWRITE_TIFF_COMPRESSION_LZMA: LZMA2
IMWRITE_TIFF_COMPRESSION_ZSTD: ZSTD: WARNING not registered in Adobe-maintained registry
IMWRITE_TIFF_COMPRESSION_WEBP: WEBP: WARNING not registered in Adobe-maintained registry
IMWRITE_TIFF_COMPRESSION_JXL: JPEGXL: WARNING not registered in Adobe-maintained registry
IMWRITE_TIFF_PREDICTOR_NONE: no prediction scheme used
IMWRITE_TIFF_PREDICTOR_HORIZONTAL: horizontal differencing
IMWRITE_TIFF_PREDICTOR_FLOATINGPOINT: floating point predictor
IMWRITE_TIFF_RESOLUTION_UNIT_NONE: no absolute unit of measurement.
IMWRITE_TIFF_RESOLUTION_UNIT_INCH: IMWRITE_TIFF_RESOLUTION_UNIT_INCH: inch
IMWRITE_TIFF_RESOLUTION_UNIT_CENTIMETER: IMWRITE_TIFF_RESOLUTION_UNIT_CENTIMETER: centimeter
IMWRITE_EXR_TYPE_HALF: store as HALF (FP16)
IMWRITE_EXR_TYPE_FLOAT: store as FP32 (default)
IMWRITE_EXR_COMPRESSION_NO: IMWRITE_EXR_COMPRESSION_NO: no compression
IMWRITE_EXR_COMPRESSION_RLE: run length encoding
IMWRITE_EXR_COMPRESSION_ZIPS: zlib compression, one scan line at a time
IMWRITE_EXR_COMPRESSION_ZIP: zlib compression, in blocks of 16 scan lines
IMWRITE_EXR_COMPRESSION_PIZ: piz-based wavelet compression
IMWRITE_EXR_COMPRESSION_PXR24: lossy 24-bit float compression
IMWRITE_EXR_COMPRESSION_B44: lossy 4-by-4 pixel block compression, fixed compression rate
IMWRITE_EXR_COMPRESSION_B44A: lossy 4-by-4 pixel block compression, flat fields are compressed more
IMWRITE_EXR_COMPRESSION_DWAA: lossy DCT based compression, in blocks of 32 scanlines. More efficient for partial buffer access. Supported since OpenEXR 2.2.0.
IMWRITE_EXR_COMPRESSION_DWAB: lossy DCT based compression, in blocks of 256 scanlines. More efficient space wise and faster to decode full frames than DWAA_COMPRESSION. Supported since OpenEXR 2.2.0.
IMWRITE_PNG_STRATEGY_DEFAULT: Use this value for normal data.
IMWRITE_PNG_STRATEGY_FILTERED: Use this value for data produced by a filter (or predictor).Filtered data consists mostly of small values with a somewhat random distribution. In this case, the compression algorithm is tuned to compress them better.
IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY: Use this value to force Huffman encoding only (no string match).
IMWRITE_PNG_STRATEGY_RLE: Use this value to limit match distances to one (run-length encoding).
IMWRITE_PNG_STRATEGY_FIXED: Using this value prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.
IMWRITE_PNG_FILTER_NONE: This is a combination of IMWRITE_PNG_FILTER_NONE, IMWRITE_PNG_FILTER_SUB, and IMWRITE_PNG_FILTER_UP, typically used for faster compression.
IMWRITE_PNG_FILTER_SUB: This is a combination of IMWRITE_PNG_FILTER_NONE, IMWRITE_PNG_FILTER_SUB, and IMWRITE_PNG_FILTER_UP, typically used for faster compression.
IMWRITE_PNG_FILTER_UP: This is a combination of IMWRITE_PNG_FILTER_NONE, IMWRITE_PNG_FILTER_SUB, and IMWRITE_PNG_FILTER_UP, typically used for faster compression.
IMWRITE_PNG_FILTER_AVG: This combines all available filters (NONE, SUB, UP, AVG, and PAETH), which will attempt to apply all of them for the best possible compression.
IMWRITE_PNG_FILTER_PAETH: This combines all available filters (NONE, SUB, UP, AVG, and PAETH), which will attempt to apply all of them for the best possible compression.
IMWRITE_PNG_FAST_FILTERS: This combines all available filters (NONE, SUB, UP, AVG, and PAETH), which will attempt to apply all of them for the best possible compression.
IMWRITE_PNG_ALL_FILTERS: This combines all available filters (NONE, SUB, UP, AVG, and PAETH), which will attempt to apply all of them for the best possible compression.
IMWRITE_PAM_FORMAT_NULL: imwrite pam format null constant (0), defined by OpenCV for cv.
IMWRITE_PAM_FORMAT_BLACKANDWHITE: imwrite pam format blackandwhite constant (1), defined by OpenCV for cv.
IMWRITE_PAM_FORMAT_GRAYSCALE: imwrite pam format grayscale constant (2), defined by OpenCV for cv.
IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA: imwrite pam format grayscale alpha constant (3), defined by OpenCV for cv.
IMWRITE_PAM_FORMAT_RGB: imwrite pam format rgb constant (4), defined by OpenCV for cv.
IMWRITE_PAM_FORMAT_RGB_ALPHA: imwrite pam format rgb alpha constant (5), defined by OpenCV for cv.
IMWRITE_WEBP_LOSSLESS_OFF: Lossy compression mode. Uses IMWRITE_WEBP_QUALITY to control compression. (Default)
IMWRITE_WEBP_LOSSLESS_ON: Standard lossless compression. May modify or discard RGB values of fully transparent pixels to improve compression ratio.
IMWRITE_WEBP_LOSSLESS_PRESERVE_COLOR: Exact lossless compression. Preserves all RGB data even for pixels with 0 alpha (equivalent to WebP's exact flag).
IMWRITE_HDR_COMPRESSION_NONE: imwrite hdr compression none constant (0), defined by OpenCV for cv.
IMWRITE_HDR_COMPRESSION_RLE: imwrite hdr compression rle constant (1), defined by OpenCV for cv.
IMWRITE_BMP_COMPRESSION_RGB: Use BI_RGB. OpenCV v4.12.0 or before supports to encode with this compression only.
IMWRITE_BMP_COMPRESSION_BITFIELDS: Use BI_BITFIELDS. OpenCV v4.13.0 or later can support to encode with this compression. (only for 32 BPP images)
IMWRITE_GIF_FAST_NO_DITHER: imwrite gif fast no dither constant (1), defined by OpenCV for cv.
IMWRITE_GIF_FAST_FLOYD_DITHER: imwrite gif fast floyd dither constant (2), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_8: imwrite gif colortable size 8 constant (3), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_16: imwrite gif colortable size 16 constant (4), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_32: imwrite gif colortable size 32 constant (5), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_64: imwrite gif colortable size 64 constant (6), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_128: imwrite gif colortable size 128 constant (7), defined by OpenCV for cv.
IMWRITE_GIF_COLORTABLE_SIZE_256: imwrite gif colortable size 256 constant (8), defined by OpenCV for cv.
IMAGE_METADATA_UNKNOWN: Used when metadata type is unrecognized or not set
IMAGE_METADATA_EXIF: EXIF metadata (e.g., camera info, GPS, orientation)
IMAGE_METADATA_XMP: XMP metadata (eXtensible Metadata Platform - Adobe format)
IMAGE_METADATA_ICCP: ICC Profile (color profile for color management)
IMAGE_METADATA_CICP: cICP Profile (video signal type)
IMAGE_METADATA_MAX: Highest valid index (usually used for bounds checking)