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fsphil / hacktv

Analogue TV transmitter for the HackRF
GNU General Public License v3.0
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Vertical Interval Test Signal (VITS) #19

Closed Zcooger closed 1 year ago

Zcooger commented 5 years ago

This ticket is made to suggest adding vertical blanking test signal (VITS) used to calibrate the image brightness, color, setting proper gain and troubleshot transmission problems.

Some docs here: https://www.semanticscholar.org/paper/Current-Usage-of-Vertical-Interval-Test-Signals-in-O'Connor/bc793d1eac9efbc02faf1596bde664c5c5d6d426 https://www.tek.com/datasheet/vm700t-option-11 Interlaced snapshots captured from my VHS tapes: RTL7 example: obraz obraz Zoomed lines - 37, 38, 39, 40 Canal+ example (with nagravision signals too): obraz obraz Zoomed lines - 37, 38, 39, 40 TVP2 example: obraz obraz Zoomed lines - 40, 41, 42, 43 obraz obraz Zoomed lines - 40, 41, 42, 43 TVP1 example: obraz obraz Zoomed lines - 41, 42, 43, 44 Discovery Channel example (with videocrypt signals too): obraz obraz Zoomed lines - 41, 42, 43, 44

Zcooger commented 5 years ago

Digital remake based on oscilloscope waveform: vits 17 VITS 17.svg

fsphil commented 5 years ago

Some more information on these test signals: http://zone.ni.com/reference/en-XX/help/373389B-01/nivms/pal_patterns/ https://www.itu.int/rec/T-REC-J.61-199006-I/en

They occupy lines 17, 18, 330 and 331 on PAL systems (and I presume SECAM as well). I will add these but not just yet, I'm busy with another project right now. Assigned to myself.

Zcooger commented 5 years ago

NTSC frame example (GGV1069 LaserDisc): obraz

Zcooger commented 4 years ago

PAL frame reference (Unknown LaserDisc): obraz

fsphil commented 4 years ago

My first go at a VITS generator is now committed. Use --vits to enable.

The phase of the chrominance signals are going to be wrong, and it's not supported on 525 line modes yet. I'll leave this issue opened until those are resolved.