Help converting jpeg2000 dcp mxf files to y4m

[sophisticles]

Hi,

I plan on running a bunch of test encodes using the various Netflix digital cinema sources, such as Meridian, but decoding jpeg2000 dcp files in real time on consumer grade hardware is not possible, it requires specialized MIPS chips, as far as I know.

As a result each test encode takes forever, as the cpu is tasked with both decoding the mxf file and encoding with aggressive settings.

Conversely, doing test encodes with the y4m version of ToS flies, as the cpu only has to encode.

So, how can I convert these files to y4m?

I think ffmpeg does it, but the I'm not quite sure about the sample command samples I have found online.

[Selur]

but decoding jpeg2000 dcp files in real time on consumer grade hardware is not possible,

At least entry level hardware won't work, since jpege2000 will be decoded by the cpu.

So, how can I convert these files to y4m?

You are aware that y4m is raw video, thus the output will be even larger than your jpeg2000 files, right?
Assuming your source is 4:4:4 12bit pc luma range, you could use:

ffmpeg -y -noautorotate -nostdin -i "G:\tos_version_05\tos_picture.mxf" -vf  scale=in_range=pc:out_range=pc -sws_flags accurate_rnd+full_chroma_inp -strict -1 -pix_fmt yuv444p12le -an -sn "g:\Test.y4m"

Side note: if you want to do encoding tests you might want to convert to something that can be decoded by your gpu/vpu instead of raw video.

Cu Selur