Table 6 – Standard filters

FILTER name

Parameters

Description

ASCIIHexDecode

no

Decodes data encoded in an ASCII hexadecimal representation, reproducing the original binary data.

ASCII85Decode

no

Decodes data encoded in an ASCII base-85 representation, reproducing the original binary data.

LZWDecode

yes

Decompresses data encoded using the LZW (Lempel-Ziv-Welch) adaptive compression method, reproducing the original text or binary data.

FlateDecode

yes

(PDF 1.2) Decompresses data encoded using the zlib/deflate compression method, reproducing the original text or binary data.

RunLengthDecode

no

Decompresses data encoded using a byte-oriented run-length encoding algorithm, reproducing the original text or binary data (typically monochrome image data, or any data that contains frequent long runs of a single byte value).

CCITTFaxDecode

yes

Decompresses data encoded using the CCITT facsimile standard, reproducing the original data (typically monochrome image data at 1 bit per pixel).

JBIG2Decode

yes

(PDF 1.4) Decompresses data encoded using the JBIG2 standard, reproducing the original monochrome (1 bit per pixel) image data (or an approximation of that data).

DCTDecode

yes

Decompresses data encoded using a DCT (discrete cosine transform) technique based on the JPEG standard, reproducing image sample data that approximates the original data.

JPXDecode

no

(PDF 1.5) Decompresses data encoded using the wavelet-based JPEG2000 standard, reproducing the original image data.

Crypt

yes

(PDF 1.5) Decrypts data encrypted by a security handler, reproducing the data as it was before encryption.