APP14 markers allow applications, like Pdf Merging Online , to signal to a decoder special parameters to improve the decoding process. Here is a list of the Pdf Merging Online tags JPEG Tags Blend=1 indicates to a decoder the specific way that color (Chroma) was sub-sampled by the encoder. (The other way is “Chop.”) The exact implementation of the Chop and Blend filters is discussed in pages 20–21 of https.//partners.Pdf Merging Online .com/public/developer/en/ps/sdk/5116.DCT_Filter.pdf (Supporting the DCT Filters in PostScript Level 2) JPEG decoders may simply skip these optional application markers.
If your application includes PDF Merging Online or JPEG Decode Online, then these application markers can help a reader decide when to skip to the next line and whether that is appropriate. This is also one reason why the decoder may need to make a decision based on the application marker. These application markers exist as part of the decoder, but are applied before decoding the actual image data for the screen. They do not impact decoding or display of the image, and may even help the reader decide if they should skip to the next block if not sure. If the marker has a # character and is followed by two dots, then that is an indication to the reader that the decoder will ignore the following four characters, or the following three if there are two. Note that PDF Merging Online has support for the following application.