Wanted support for compressed DNG

[stevefal]

I use Adobe Digital Negative Converter to convert RAWMagic-produced DNGs to losslessly compressed versions. This cuts the file size by 50%.

But MlRawViewer does not seem to support these. Upon selecting such a file, MlRawViewer silently exits.

[Andrew Baldwin]

Agree this would be good for both playback and export.

Problem is, right now there is no open source Jpeg (1992) lossless imlementation (that's the DNG lossless codec) code I could use easily.

dcraw has a decoder, but it's quite embedded in the rest of the dcraw code.

Ideally I would like to see a good encoder/decoder, and then use that for read and export. Also it wouild be good for MLV to support that codec allowing compressed frames which could be copied as-is into DNGs.

[stevefal]

I assumed the Adobe DNG SDK would be a suitable source and license.

/*****************************************************************************/

void DecodeLosslessJPEG (dng_stream &stream,
                         dng_spooler &spooler,
                         uint32 minDecodedSize,
                         uint32 maxDecodedSize,
                         bool bug16);

/*****************************************************************************/

void EncodeLosslessJPEG (const uint16 *srcData,
                         uint32 srcRows,
                         uint32 srcCols,
                         uint32 srcChannels,
                         uint32 srcBitDepth,
                         int32 srcRowStep,
                         int32 srcColStep,
                         dng_stream &stream);

/*****************************************************************************/

[Andrew Baldwin]

Even ignoring the license, there is no Linux version of the Adobe DNG SDK, and since I use Linux for all MlRawViewer development that's not practical for me to use.

[stevefal]

I wonder what this guy used: http://www.magiclantern.fm/forum/index.php?topic=7825.0

[Andrew Baldwin]

Good find. Text says "Using the Adobe DNG SDK (full DNG support)".

I'll investigate more how/if Adobe's SDK can be used with Linux after all.

[Andrew Baldwin]

Compressed DNG was implemented in 1.3.0

I haven't actually tested it with this use case though, so it's possible it won't actually handle the output of Adobe's SDK.

It does read the compressed DNGs from BMPCC cameras however.

[stevefal]

As far as I can tell it doesn't read from Adobe. I've converted a clip using Adobe DNG Converter and it doesn't show up in the browser.

[Andrew Baldwin]

Can you provide a sample DNG for me to test with.