[Request] Implementing JPG exporting

[Selur]

Got any documentation regarding how to use ffmpeg for jpeg creation?

Using

ffmpeg -h encoder=libopenjpg

I get

Encoder libopenjpeg [OpenJPEG JPEG 2000]:
    General capabilities: threads
    Threading capabilities: frame
    Supported pixel formats: rgb24 rgba rgb48le rgba64le gbrp gbrp9le gbrp10le gbrp12le gbrp14le gbrp16le gray ya8 gray16le ya16le gray10le gray12le gray14le yuv420p yuv422p yuva420p yuv440p yuv444p yuva422p yuv411p yuv410p yuva444p yuv420p9le yuv422p9le yuv444p9le yuva420p9le yuva422p9le yuva444p9le yuv420p10le yuv422p10le yuv444p10le yuva420p10le yuva422p10le yuva444p10le yuv420p12le yuv422p12le yuv444p12le yuv420p14le yuv422p14le yuv444p14le yuv420p16le yuv422p16le yuv444p16le yuva420p16le yuva422p16le yuva444p16le xyz12le
libopenjpeg AVOptions:
  -format            <int>        E..V....... Codec Format (from 0 to 2) (default jp2)
     j2k             0            E..V.......
     jp2             2            E..V.......
  -profile           <int>        E..V....... (from 0 to 4) (default jpeg2000)
     jpeg2000        0            E..V.......
     cinema2k        3            E..V.......
     cinema4k        4            E..V.......
  -cinema_mode       <int>        E..V....... Digital Cinema (from 0 to 3) (default off)
     off             0            E..V.......
     2k_24           1            E..V.......
     2k_48           2            E..V.......
     4k_24           3            E..V.......
  -prog_order        <int>        E..V....... Progression Order (from 0 to 4) (default lrcp)
     lrcp            0            E..V.......
     rlcp            1            E..V.......
     rpcl            2            E..V.......
     pcrl            3            E..V.......
     cprl            4            E..V.......
  -numresolution     <int>        E..V....... (from 0 to 33) (default 6)
  -irreversible      <int>        E..V....... (from 0 to 1) (default 0)
  -disto_alloc       <int>        E..V....... (from 0 to 1) (default 1)
  -fixed_quality     <int>        E..V....... (from 0 to 1) (default 0)

using:

ffmpeg -h encoder=jpeg2000

I get:

Encoder jpeg2000 [JPEG 2000]:
    General capabilities: none
    Threading capabilities: none
    Supported pixel formats: rgb24 yuv444p gray yuv420p yuv422p yuv410p yuv411p pal8 rgb48le gray16le
jpeg 2000 encoder AVOptions:
  -format            <int>        E..V....... Codec Format (from 0 to 1) (default jp2)
     j2k             0            E..V.......
     jp2             1            E..V.......
  -tile_width        <int>        E..V....... Tile Width (from 1 to 1.07374e+09) (default 256)
  -tile_height       <int>        E..V....... Tile Height (from 1 to 1.07374e+09) (default 256)
  -pred              <int>        E..V....... DWT Type (from 0 to 1) (default dwt97int)
     dwt97int        0            E..V.......
     dwt53           0            E..V.......
  -sop               <int>        E..V....... SOP marker (from 0 to 1) (default 0)
  -eph               <int>        E..V....... EPH marker (from 0 to 1) (default 0)
  -prog              <int>        E..V....... Progression Order (from 0 to 4) (default lrcp)
     lrcp            0            E..V.......
     rlcp            1            E..V.......
     rpcl            2            E..V.......
     pcrl            3            E..V.......
     cprl            4            E..V.......
  -layer_rates       <string>     E..V....... Layer Rates

There's also jpegls, ljpeg, mjpeg.

Problem is I see no documentation what the options really do. (Last time I read up on jpeg compression was 20+ years ago,...)

Also are you use writing the pngs is the bottleneck on your processing in Hybrid ? (usually it's the filtering or decoding, when it's not the encoder)

JPG encoding could bring significant speed boosts to my entire workflow and it would be very helpful.

Out of curiousity: What is your workflow that using lossy jpeg compression it worth it?


Cu Selur