The entire wiki has been moved to a GitHub pages site: ld-decode documentation

The reason for this change is to both modernize the documentation and make it possible for anyone to update, change and correct the documentation through the standard GitHub PR mechanisms. If you are interested in contributing to the documentation please see the instructions available from the ld-decode documentation GitHub

The original wiki page below will be available until 2025-12-20. Do not update this wiki.

The ld-decode.py application accepts FM RF captures input in '10-bit packed' format. This is a bit-stream of 10-bit unsigned integers produced by the Domesday Duplicator's capture GUI (typically with the .lds file extension). The input bit-stream is expected to be the raw LaserDisc RF captured at 40 Million Samples Per Second (MSPS) with each sample being 10-bits.

*The decoder also supports FLAC compressed captures, and lower sample rates if the input frequency is defined and bit-depths such as 8-bit & 16-bit.

The output from ld-decode.py is a stream of 16-bit unsigned values; each value representing a single grey-scale value. The file extension used by ld-decode is .tbc for both NTSC and PAL decoded frames aptly named the Time Base Corrected format.

PAL output is 1135x625 16-bit values. (280mbps) (2.1GB/min) (126GB/hour)

NTSC output is 910x525 16-bit values. (226.5mbps) (1.7GB/min) (102GB/hour)

The 16-bit grey-scale values used by the output format are scaled representations of the standard 8-bit digital component values (i.e. an 8-bit right shift of the value will provide the standard 8-bit digital component intensity values).

The frequency values for .tbc to analogue CVBS playback via DAC are the following:

PAL - 17727262 Hz

NTSC - 14318181 Hz

The NTSC and PAL chroma-decoders (a.k.a. comb filters) accept .tbc files from the ld-decode.py application and produces a raw RGB bit-stream with 16 bits per color value in the order RGB16-16-16 giving 48-bits per pixel. The file extension is .rgb (and can be used by applications such as ffmpeg by specifying the raw RGB format with a depth of 16.

Examples of pre-made export commands for FFV1/V210/V410 & ProRes-HQ/ProRes4444XQ codecs can be found here

The following file sizes show the typical disc usage consumed by an end-to-end capture and decode of a LaserDisc.

Individual decodes will vary from disc-to-disc:

• NPE - PAL CAV disc with 54348 frames
• NPE - LDS (RF Capture 40MSPS 10-bit packed) = 109.4GB
• NPE - LDF (RF Capture 40MSPS 16-bit FLAC compressed) = 22.6GB (Estimate*)
• NPE - TBC (Indexed16) = 77.1GB
• NPE - PCM (48K little Endian 16-bit signed) = 417.4MB
• NPE - RGB (RGB 16-16-16) = 175.6GB
• NPE - AVI (36min 13sec mp4) = 4.1GB

Raw 10-bit Packed DomesDayDuplicator Captures are 2.8GB/Min when compressed via ld-compress this becomes around 625MB/Min in 16-bit FLAC which is still decodable with a small processing speed penalty on solid state media.