ld decode tools
ld-decode-tools is a suite of applications for processing the .tbc, _chroma.tbc & .JSON output files from the suite of decoders.
The tools enable various processing of time base corrected analogue video signals including VBI such as but not limited to
- VITS Vertical Interval Test Signals
- VITC SMPTE Vertical Interval TimeCode
- Closed Captioning
- 40-bit FM code,
- White-Flag
- Dropout Detection/Correction
- Comb Filtering.
The tools suite use a JSON based metadata file workflow to store and communicate information about every frame/field of the decoded .tbc files.
Details of the JSON format can be found on the JSON Metadata format wiki pages.
ld-process-vbi test_video.tbc (add in the VBI data and determine the field order)
ld-dropout-correct test_video_map.tbc test_video_mapdoc.tbc (correct the dropouts and create a new .tbc)
ld-analyse test_video_mapdoc.tbc & (view the corrected .tbc)
ld-chroma-decoder test_video_mapdoc.tbc test_video_mapdoc.rgb (convert the .tbc to RGB 16-16-16 frames)
For a PAL .tbc output file a typical sequence would be:
ld-process-vbi test_video.tbc (add in the VBI data and determine the field order)
ld-discmap test_video.tbc test_video_map.tbc (maps the disc and removes duplicate frames)
ld-dropout-correct test_video.tbc test_video_doc.tbc (correct the dropouts and create a new .tbc)
ld-analyse test_video_doc.tbc & (view the corrected .tbc)
ld-chroma-decoder test_video_doc.tbc test_video_doc.rgb (convert the .tbc to RGB 16-16-16 frames)
Note
That the VBI processing, NTSC processing, disc-mapping, drop-out detection and correction are optional.
This application examines the input TBC file and determines the available VBI data for each available frame.
The VBI data is stored as both the raw data value for the 3 VBI lines as well as a full decode of the VBI according to the IEC specifications. The resulting information is written back into the JSON metadata file for the TBC output and supported by ld-analyse & ld-metadata-export.
Currently Supporting:
- VITC Timecode
- Closed Captions
- 40-bit FM Codes (NTSC LaserDiscs)
- White Flags (NTSC LaserDiscs)
Syntax:
ld-process-vbi <options> <input TBC file name>
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
--input-json <filename> Specify the input JSON file (default input.json)
--output-json <filename> Specify the output JSON file (default same as
input)
-n, --nobackup Do not create a backup of the input JSON metadata
-t, --threads <number> Specify the number of concurrent threads (default
is the number of logical CPUs)
Arguments:
input Specify input TBC file
This application performs an analysis of the VITS (Vertical Interval Test Signals) and recalculates the white and black SNR values in the metadata. Note that any TBC file will already have this metadata provided by ld-decode. This tool is generally used along with dropout correction and stacking as the video content of the TBC is modified - running ld-process-vits therefore allows you update the SNR metadata in order to analyse the result (using ld-analyse).
Use the tool by specifying the required input .tbc file. The tool will backup the previous JSON file (to .vbup) before proceeding.
Options:
-h, --help Displays this help.
-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)
--output-json <filename> Specify the output JSON file (default same as
input)
-n, --nobackup Do not create a backup of the input JSON metadata
-t, --threads <number> Specify the number of concurrent threads (default
is the number of logical CPUs)
Arguments:
input Specify input TBC file
This application reads a JSON metadata file, typically as produced by ld-process-vbi, and exports information in standard formats that other tools can read. At present, it can export:
- Per-frame signal quality information from the VITS test signals, as CSV
- Per-frame LaserDisc VBI control signals, as CSV
- LaserDisc navigation information, as FFMETADATA1 (which FFmpeg can use to add chapter navigation to a video file)
- Closed Captions, as SCC format (which tools like ttconv can read)
Syntax:
ld-export-metadata <options> <input>
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
--vits-csv <file> Write VITS information as CSV
--vbi-csv <file> Write VBI information as CSV
--ffmetadata <file> Write navigation information as FFMETADATA1
--closed-captions <file> Write closed captions as Scenarist SCC V1.0 format
Arguments:
input Specify input JSON file
This application uses the drop-out information in the JSON metadata file to perform dropout correction on the input TBC file and produces a new output file. The current version of the corrector uses framing in order to provide inter-field correction.
Note
That inter-field correction may not function correctly for NTSC pull-down sources.
Syntax:
ld-dropout-correct <options> <input TBC file name> <output TBC file name>
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
--input-json <filename> Specify the input JSON file (default input.json)
--output-json <filename> Specify the output JSON file (default output.json)
-r, --reverse Reverse the field order to second/first (default
first/second)
-o, --overcorrect Over correct mode (use on heavily damaged sources)
-i, --intra Force intrafield correction (default interfield)
-t, --threads <number> Specify the number of concurrent threads (default
is the number of logical CPUs)
Arguments:
input Specify input TBC file (- for piped input)
output Specify output TBC file (omit or - for piped
output)
This application takes the PAL or NTSC TBC input video 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 RGB file name>)
The output RGB file name is optional. If omitted the output will be sent to stdout (for pipe-lining).
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
Most of the options here correspond to settings in ld-analyse's 'Chroma decoder configuration' window, so you can experiment with them interactively using ld-analyse. For more information on what the settings mean, see the ld-analyse User Guide.
The mono filter isn't available in ld-analyse. It treats the whole signal as being 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 this help.
-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)
-b, --blackandwhite Output in black and white
-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)
-o, --oftest NTSC: Overlay the adaptive filter map (only
used for testing)
-w, --white NTSC: Use 75% white-point (default 100%)
--chroma-nr <number> NTSC: Chroma noise reduction level in dB
(default 0.0)
--luma-nr <number> NTSC: Luma noise reduction level in dB
(default 1.0)
--simple-pal Transform: Use 1D UV filter (default 2D)
--transform-mode <mode> Transform: Filter mode to use (level,
threshold; default threshold)
--transform-threshold <number> Transform: Uniform similarity threshold in
'threshold' mode (default 0.4)
--transform-thresholds <file> Transform: File containing per-bin similarity
thresholds in 'threshold' mode
--show-ffts Transform: Overlay the input and output FFTs
Arguments:
input Specify input TBC file (- for piped input)
output Specify output RGB file (omit or - for piped
output)
For more information about ld-analyse please see the dedicated ld-analyse User Guide wiki page.
This GUI application provides a range of features for examining TBC output including drop-out detection, video extent, line scope and VBI data. The application works with NTSC and PAL TBC output files.
2022 Version (Rev 7)
Note
The input file name is optional (you can either specify it from the command line or using the GUI once the application is running).
Syntax:
ld-analyse <options> <input TBC file name>
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
Arguments:
input Specify input TBC file
This application processes the .efm output from ld-decode (LaserDisc Only) into either digital audio or data. The application implements both audio and data error detection and correction.
Audio output is a stereo 44.1KHz 16-bit PCM file.
Note
That this tool can be run as an interactive GUI or non-interactive via the CLI. Many more decoding options are available in the GUI for more complex EFM processing.
Syntax:
ld-process-efm <options> <input EFM file name> (<output PCM file name>)
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
-n, --noninteractive Run in non-interactive mode
Arguments:
input Specify input EFM file
output Specify output audio file
Extra command line options to allow running headless or via ssh -platform offscreen (This is supplied via QT and is not part of the application itself and should be included in the <options> section.)
Note
As of 2023 there future builds no longer have the GUI.
GUI options:
- Audio
- Conceal corrupt audio data - Attempts to conceal corrupt audio data using the concealment type selected in the following section
- Silence corrupt audio data - Silences any corrupt samples
- Pass-through corrupt audio data - Passes any corrupt samples through to the output as-is
- Concealment type
- Linear interpolation - Interpolates between last-good and next-good samples to conceal errors
- Interpolated error prediction - Experimental (not recommended)
- Options
- Pad start of audio from 00:00 to match initial disc time - Pads the start of the input sample to ensure the output starts from the 00:00 time of the disc. Useful for assembling partial captures.
- Decode F1 frames as audio - Always decode F1 frames as if they contain audio data (useful for older discs)
- Decode F1 frames as data - Always decode F1 frames as if they contain data (useful for older IV discs)
- Non-standard audio decode (no time-stamp information)
- Development
- EFM to F3 Frame debug
- F3 and section debug
- F3 to F2 Frame decoding debug
- F2 to F1 Frame decoding debug
- F1 Frame to audio samples debug
- F1 Frame to data sector debug
This application can accept 10-bit packed format .lds files and convert them to 16-bit signed files or vice-versa (useful for expanding .lds files and piping the output to a compression utility such as FLAC).
Syntax:
ld-lds-converter <options>
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
-i, --input <file> Specify input laserdisc sample file (default is stdin)
-o, --output <file> Specify output laserdisc sample file (default is stdout)
-u, --unpack Unpack 10-bit data into 16-bit (default)
-p, --pack Pack 16-bit data into 10-bit
This application scans through the metadata for a .tbc file and attempts to correct metadata and video data to ensure the .tbc contains the correct amount of frames, in the right order, without duplication. The application also pads the .tbc with dummy (black) frames when one or more frames are missing.
It is recommended to run ld-process-vbi on the input .tbc before running this tool.
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
-r, --reverse Reverse the field order to second/first (default first/second)
-m, --maponly Only perform mapping, but do not save to target (for testing
purposes)
Arguments:
input Specify input TBC file
output Specify output TBC file
This application performs 'stacking' of multiple versions of the same disc (ideally different copies of discs containing the same mastered contents). Disc stacking requires a minimum of two input sources in order to work (although 3 or more are strongly recommended).
Stacking is performed by taking all available input sources and, pixel by pixel, determining the number of available sources for the pixel (by removing outliers marked as dropouts in the source files). If more than 3 sources are available for the pixel the tool will use the median value of the available sources as the output (when there are an even number available of pixel sources, the two centre values of the median are averaged to the output). If only two sources are available an average is used. If only one source is available it is passed directly as the output.
If no sources are available for a pixel the tool will attempt to use differential dropout detection (diffDOD) to recover a value (in the case where ld-decode marked the pixel as a false-negative) unless the --no-diffdod option is specified.
If the --passthrough option is specified the tool will, when all pixel sources are marked as a dropout, mark the resulting output pixel as a dropout (regardless of the diffDOD result). The --passthrough is useful in non-preservation cases where it is desirable for master plate errors (which cause dropouts in the same place on all resulting LaserDisc copies) to be marked for dropout concealment (where-as diffDOD would correctly identify the plate error as present on all discs (and therefore not an error)).
Use the tool by specifying the available input .tbc files followed by the desired .tbc output file.
Options:
-h, --help Displays this help.
-v, --version Displays version information.
-d, --debug Show debug
-q, --quiet Suppress info and warning messages
--input-json <filename> Specify the input JSON file for the first input
file (default input.json)
--output-json <filename> Specify the output JSON file (default output.json)
-r, --reverse Reverse the field order to second/first (default
first/second)
-t, --threads <number> Specify the number of concurrent threads (default
is the number of logical CPUs)
--no-diffdod Do not use differential dropout detection on low
source pixels
--passthrough Pass-through dropouts present on every source
Arguments:
inputs Specify input TBC files (- as first source for
piped input)
output Specify output TBC file (omit or - for piped
output)
This application does the opposite of ld-chroma-decoder.
It reads a stream of RGB48 or YUV444P16 frames, encodes them into a PAL or NTSC Composite signal, and writes a single or TBC file as output for S-Video it can write two TBC files.
It's primarily useful for testing and development purposes. For example, you can use it to generate TBC files from standard test videos and then look at the effects of decoding them with different options in ld-analyse or ld-chroma-decoder.
The input is assumed to be either
928x576 for PAL (top field first)
758x486 for NTSC (bottom field first)
Syntax:
ld-chroma-encoder <options> <input file name> <output TBC file name> [<output chroma TBC file name>]
Specify the input filename as - to read from standard input.
If you specify a chroma TBC filename syncs and luma are written to the main TBC and chroma is written to the chroma TBC. (same as vhs-decode output)
This is particularly useful for calibrating chroma filters (e.g. Transform PAL) since it gives you the "ideal" output from the filter to compare against.
To use a standard video file as an input source to create an TBC file
NTSC
CVBS (Single .TBC)
ffmpeg -i INPUT.mkv -an -vf "scale=758:480,pad=758:486:0:3" -vcodec rawvideo -pix_fmt yuv444p16 -f rawvideo - | ld-chroma-encoder -p yuv -f NTSC - OUTPUT.tbc
S-Video (Two .TBC)
ffmpeg -i INPUT.mkv -an -vf "scale=758:480,pad=758:486:0:3" -vcodec rawvideo -pix_fmt yuv444p16 -f rawvideo - | ld-chroma-encoder -p yuv -f NTSC - OUTPUT.tbc OUTPUT_chroma.tbc
PAL
CVBS (Single .TBC)
ffmpeg -i INPUT.mkv -an -vf "scale=922:576,pad=922:576:0:3" -vcodec rawvideo -pix_fmt yuv444p16 -f rawvideo - | ld-chroma-encoder -p yuv -f PAL - OUTPUT.tbc
S-Video (Two .TBC)
ffmpeg -i INPUT.mkv -an -vf "scale=922:576,pad=922:576:0:3" -vcodec rawvideo -pix_fmt yuv444p16 -f rawvideo - | ld-chroma-encoder -p yuv -f PAL - OUTPUT.tbc OUPUT_chroma.tbc
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
-f, --system <system> Video system (PAL, NTSC; default PAL)
-p, --input-format <input-format> Input format (rgb, yuv; default rgb);
RGB48, YUV444P16 formats are supported
--field-offset <offset> Offset of the first output field within
the field sequence (0, 2 for NTSC; 0, 2, 4,
6 for PAL; default: 0)
--chroma-mode <chroma-mode> NTSC: Chroma encoder mode to use
(wideband-yuv, wideband-yiq, narrowband-q;
default: wideband-yuv)
--no-setup NTSC: Output NTSC-J, without 7.5 IRE setup
-c, --sc-locked PAL: Output samples are subcarrier-locked
(default: line-locked)
Arguments:
input Specify input RGB file (- for piped input)
output Specify output TBC file
chroma Specify chroma output TBC file (optional)
The tools are as of 2024 available in self contained binary's or installed manually.
mkdir build2
cd build2
cmake .. -DCMAKE_BUILD_TYPE=Release -DUSE_QT_VERSION=5
make -j4
sudo make install # to install (optional, can also be ran without installing)
Note: -DUSE_QT_VERSION=5 is needed if both qt5 and qt6 are installed but qwt is only available for qt5. This is the case on e.g ubuntu and debian as of early 2023. If wanting to use qt6 and qt6 version of qwt is available but both are installed change to 6.
Note: If updating from an older release that used qmake to one that used cmake you may have to start with a fresh checkout as remnants of the qmake build can cause issues for a new cmake build.
cd vhs-decode && make -j8 && sudo make install && make clean
Use sudo make uninstall to remove.
From the tools directory (of the ld-decode repo) type 'qmake' followed by 'make all'. Once all of the applications are compiled use 'sudo make install' to install and
Note: The ld-decode-tools.pro qmake project file is designed only for command line compilation with Ubuntu. The individual application .pro files can be used within the Qt Creator IDE (you should build ld-decode-shared first in order to make a local copy of the required shared libraries).
So if, for example, your .tbc output file is test_video.tbc (and is NTSC):
Note: If compilation fails after pulling a new version of the tools from github, try running the following commands in the tools/ directory before filing a github issue report:
make distclean
qmake
make all
sudo make install
Next Page: Command List
- FAQ - Frequently Asked Questions
- Diagram Breakdowns
- Visual-Comparisons
- VCR Reports / RF Tap Examples
- Download & Contribute Data
- Speed Testing
- Visual VBI Data Guide
- Closed Captioning
- Teletext
- WSS Wide - Screen Signalling
- VITC Timecode
- VITS Signals
- XDS Data (PBS)
- Video ID IEC 61880
- Vapoursynth TBC Median Stacking Guide
- Ruxpin-Decode & TV Teddy Tapes
- Tony's GNU Radio For Dummies Guide
- Tony's GNU Radio Scripts
- DomesDay Duplicator Utilities
- ld-decode Utilities