Problem

Orc currently only supports NTSC and PAL-N, which limits its usability for Brazilian analog video formats. but vhs-decode supports pal-m and unnoficially n-linha (using custom .jsons)

Proposed Solution

Add support for PAL-M, as well as handling of a legacy modification known as N-LINHA.

Background

PAL-M

PAL-M is the standard analog TV system used in Brazil.

• 525 lines / 60 Hz (same as NTSC)
• PAL color encoding (different from NTSC)
• Not directly compatible with NTSC or PAL-N decoding

Because of this hybrid nature, PAL-M requires specific decoding logic.

N-LINHA (Pre-PAL-M workaround)

Before PAL-M VCRs were widely available, some NTSC VCRs were modified to partially support PAL-M recordings using a system known as N-LINHA.

This approach introduced several playback issues:

• On unmodified NTSC VCRs:

  • Colors appear, but are out of phase (incorrect hue)

• On PAL-M VCRs:

  • Colors appear only briefly and are highly unstable

This suggests that N-LINHA uses a non-standard or partially compatible chroma encoding.

Implementation Ideas

• Add Native support for N-LINHA tapes on vhs-decode and orc:

  • Detect abnormal chroma phase behavior
  • Apply phase correction or adaptive decoding
  • Possibly expose as an experimental mode

• Add PAL-M support on orc

Example: N-LINHA Tape

https://www.youtube.com/watch?v=8uBlQk80yjw

Why This Matters

• PAL-M is widely used in Brazil
• Many VHS and broadcast archives depend on it
• Supporting it would significantly expand Orc usability
• N-LINHA support would help recover rare legacy recordings