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Harry Munday edited this page Feb 14, 2024 · 1 revision

ld-chroma-decoder

This application takes the output of ld-decode (a PAL or NTSC TBC file) and performs chroma decoding (i.e. colourises it).

The output is a sequence of RGB48, YUV444P16, or GRAY16 video frames suitable for piping to an external application such as FFmpeg.

Syntax:

ld-chroma-decoder [options] <input TBC file name> [output file name]

Example:

TBC --> Chroma-Decoder y4m --> FFmpeg --> V210 4:2:2 Uncompressed in the QuickTime MOV contaienr.

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v210 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v210 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

Example with full vertical VBI data:

Y4M Only.

NTSC

ld-chroma-decoder --ffll 1 --lfll 259 --ffrl 2 --lfrl 525 --decoder ntsc3d -p y4m -q INPUT.tbc OUTPUT.mov

PAL

ld-chroma-decoder --ffll 2 --lfll 308 --ffrl 2 --lfrl 620 --decoder transform3d -p y4m -q INPUT.tbc OUTPUT.mov

Notes & Command Argument List

Most options have a corresponding setting in ld-analyse's 'Chroma decoder configuration' window so you can experiment with them interactively there. For more information, see the ld-analyse manual.

The mono filter isn't available in ld-analyse. It treats the whole signal as luma, so it's the best choice when you know that the input video doesn't contain any colour information (e.g. black-and-white films).

Options:
  -h, --help                                  Displays help on commandline
                                              options.
  --help-all                                  Displays help including Qt
                                              specific options.
  -v, --version                               Displays version information.
  -d, --debug                                 Show debug
  -q, --quiet                                 Suppress info and warning
                                              messages
  --input-json <filename>                     Specify the input JSON file
                                              (default input.json)
  -s, --start <number>                        Specify the start frame number
  -l, --length <number>                       Specify the length (number of
                                              frames to process)
  -r, --reverse                               Reverse the field order to
                                              second/first (default
                                              first/second)
  --chroma-gain <number>                      Gain factor applied to chroma
                                              components (default 1.0)
  --chroma-phase <number>                     Phase rotation applied to chroma
                                              components (degrees; default 0.0)
  
  -p, --output-format <output-format>         Output format (rgb, yuv, y4m;
                                              default rgb); RGB48, YUV444P16,
                                              GRAY16 pixel formats are supported
  -b, --blackandwhite                         Output in black and white

  --pad, --output-padding <number>            Pad the output frame to a
                                              multiple of this many pixels on
                                              both axes (1 means no padding,
                                              maximum is 32)
  -f, --decoder <decoder>                     Decoder to use (pal2d,
                                              transform2d, transform3d, ntsc1d,
                                              ntsc2d, ntsc3d, ntsc3dnoadapt,
                                              mono; default automatic)
  -t, --threads <number>                      Specify the number of concurrent
                                              threads (default number of logical
                                              CPUs)
  --ffll, --first_active_field_line <number>  The first visible line of a
                                              field. Range 1-259 for NTSC
                                              (default: 20), 2-308 for PAL
                                              (default: 22)
  --lfll, --last_active_field_line <number>   The last visible line of a field.
                                              Range 1-259 for NTSC (default:
                                              259), 2-308 for PAL (default: 308)
  --ffrl, --first_active_frame_line <number>  The first visible line of a
                                              frame. Range 1-525 for NTSC
                                              (default: 40), 1-620 for PAL
                                              (default: 44)
  --lfrl, --last_active_frame_line <number>   The last visible line of a frame.
                                              Range 1-525 for NTSC (default:
                                              525), 1-620 for PAL (default: 620)
  -o, --oftest                                NTSC: Overlay the adaptive filter
                                              map (only used for testing)
  --chroma-nr <number>                        NTSC: Chroma noise reduction
                                              level in dB (default 0.0)
  --luma-nr <number>                          Luma noise reduction level in dB
                                              (default 1.0)
  --ntsc-phase-comp                           NTSC: Adjust phase per-line using
                                              burst phase
  --simple-pal                                Transform: Use 1D UV filter
                                              (default 2D)
  --transform-threshold <number>              Transform: Uniform similarity
                                              threshold (default 0.4)
  --transform-thresholds <file>               Transform: File containing
                                              per-bin similarity thresholds
  --show-ffts                                 Transform: Overlay the input and
                                              output FFTs

Arguments:
  input                                       Specify input TBC file (- for piped input)
  output                                      Specify output file (omit or - for piped output)

Manual Commands

CVBS-Decode is the same workflow as Laserdisc's in with LD-Decode (without audio etc) using the suite of ld-tools.

ld-chroma-decoder is used to render the TBC to a full-colour video file you can render to y4m or pipe to FFmpeg.

The chroma-decoder can use over 20~35GB of ram if available and can run faster then real-time on fairly modern systems.

The decoder has lots of options that can be tweaked but the list of pre-made commands below will get you started with a good basic export with proper interlaced flagging.

Use ld-chroma-decoder -h to list all the options available to the decoder.

Replace INPUT.tbc and OUTPUT.mkv with your desired names.

Note

For standard output this list of export commands is provided you only need to change setdar=4/3 to setdar=16/9 for widescreen content.

Pre-Made Command List

Full Vertical Export (VBI Area)

Y4M Only* you can use these 2 commands. (Will be resolved with tbc-video-export later)

NTSC

ld-chroma-decoder --ffll 1 --lfll 259 --ffrl 2 --lfrl 525 --decoder ntsc3d -p y4m -q INPUT.tbc OUTPUT.mov

PAL

ld-chroma-decoder --ffll 2 --lfll 308 --ffrl 2 --lfrl 620 --decoder transform3d -p y4m -q INPUT.tbc OUTPUT.mov

Example To Update Later

FFV1 (4:2:2) (Lossless Compressed)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v ffv1 -level 3 -coder 1 -context 1 -g 1 -slicecrc 1 -vf setfield=tff -flags +ilme+ildct -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -pix_fmt yuv422p10le -vf setdar=4/3,setfield=tff OUTPUT.mkv

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v ffv1 -level 3 -coder 1 -context 1 -g 1 -slicecrc 1 -vf setfield=tff -flags +ilme+ildct -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -pix_fmt yuv422p10le -vf setdar=4/3,setfield=tff OUTPUT.mkv

V210 (4:2:2) (Uncompressed)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v210 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v210 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

ProRes HQ (4:2:2) (Visually Lossless)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v prores -profile:v 3 -vendor apl0 -bits_per_mb 8000 -quant_mat hq -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v prores -profile:v 3 -vendor apl0 -bits_per_mb 8000 -quant_mat hq -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv422p10le -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

Y4M (4:4:4) (Uncompressed)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc OUTPUT.mov

V410 (4:4:4) (Uncompressed)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v410 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv444p10le -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v v410 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv444p10le -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

ProRes 4444XQ (4:4:4) (Visually Lossless)

NTSC

ld-chroma-decoder --decoder ntsc3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v prores -profile:v 5 -vendor apl0 -bits_per_mb 8000 -mbs_per_slice -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv444p10le -color_primaries smpte170m -color_trc bt709 -colorspace smpte170m -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

PAL

ld-chroma-decoder --decoder transform3d -p y4m -q INPUT.tbc| ffmpeg -i - -c:v prores -profile:v 5 -vendor apl0 -bits_per_mb 8000 -mbs_per_slice 8 -f mov -top 1 -vf setfield=tff -flags +ilme+ildct -pix_fmt yuv444p10le -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range tv -vf setdar=4/3,setfield=tff OUTPUT.mov

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