Dynamically scaled file encoding

A method of scaling a file to produce an encoded file having a file size less than a file size constraint, the method comprising:

• determining a target bit rate;
• determining an initial scale factor;
• encoding a source file using quantization parameters scaled with the initial scale factor to produce an initial encoded file;
• determining a revised bit rate;
• determining a scaling factor;
• and
• re-encoding the source file using quantization parameters scaled with the scaling factor to produce the encoded file.

A method of scaling a file to produce an encoded file having a file size less than a file size constraint, the method comprising:

• estimating a number of DC bits in an image file;
• subtracting the number of DC bits from a target file size to produce an AC bit estimate;
• determining a target rate as the value of the AC bit estimate divided by a number of pixels in the image file;
• determining an initial scale factor based in part on the target rate;
• encoding the image file with a JPEG encoder using quantization parameters scaled by the initial scale factor to produce the encoded file.

One or more storage devices configured to store one or more processor readable instructions when executed by a processor, perform the method comprising:

• determining a target bit rate;
• determining an initial scale factor;
• encoding a source file using quantization parameters scaled with the initial scale factor to produce an initial encoded file;
• determining a revised bit rate;
• determining a scaling factor;
• and
• re-encoding the source file using quantization parameters scaled with the scaling factor to produce the encoded file.

A method of scaling a file to produce an encoded file having a file size less than a file size constraint, the method comprising:

• encoding a source file using an initial quantization table to produce an initial encoded file;
• determining a rate distortion curve based on the initial encoded file;
• determining a scaling factor based in part on the rate distortion curve;
• determining a scaled quantization table by scaling the initial quantization table by the scaling factor;
• and
• re-encoding the source file using the scaled quantization table to generate the encoded file.

A method of scaling a file to produce an encoded file having a file size less than a file size constraint, the method comprising:

• encoding a source file using an initial quantization table to produce an initial encoded file;
• gathering statistics from the initial encoded file;
• determining a number of zero DCT outputs from an encoder corresponding to each of a plurality of scaled quantization tables;
• determining a target number of bits;
• determining a rate distortion curve based in part on the statistics;
• determining a target fractional non-zero value based in part on the rate distortion curve;
• determining a scaling factor based in part on the target fractional non-zero value;
• applying the scaling factor to the initial quantization table to produce a target quantization table;
• and
• re-encoding the source file using the target quantization table to produce the encoded file.