SIGNAL INGEST IN UNCOMPROMISING, LINEAR VIDEO ARCHIVING:PITFALLS, LOOPHOLES AND SOLUTIONS

Franz PavuzaPhonogrammarchiv

Vienna

STATUS:Considerable analog video footage, sometimes questionable storage conditions

SOLUTION:Digitisation, adequate storage, migration

PROBLEMS:(Cost, compression, standards, storage media, metadata…..),Signal ingest

Playback devices (+service manuals, maintenance equipment)

Supporting devices (synchroniser/converter)

“Upgrades”? (replacement; enhancement)

PC/Mac-compatible workstation?

Interface (A/D-converter)

SIGNAL INGEST

DIGITISATION

Plug-in A/D card or external A/D module? (consumer- or professional devices)

Input signal flexibility?

Digital signal representation (compressed, uncompressed)

“Fast” PC (hard disk array)

“Archiving” software (for processing and backup)

CONVERTER ISSUES

Speed

Resolution

Errors

Technology (monolithic, multi-chip)

Support circuits (sample&hold circuits, filters, references)

costs: € 50.- to > € 10000.- for complete A/D module

CONVERTER ISSUES

SPEED: Video sampling (ITU-601 4:2:2)

13,5 MHz (b/w) 6,75 MHz (colour)

Modern ADCs:

12 bit/210 MSPS (monolithic)12 bit/400 MSPS (multi-chip)14 bit/105 MSPS (monolithic)16 bit/105 MSPS (multi-chip)

CONVERTER ISSUES

RESOLUTION: 8 bit – 16 bit

< 8 bit…. contouring 3 x 8 bit (“component” signal):

16 Mill. colour shades; OK with excellent ADC and no editing

3 x 12 bit: perfect for archives (expensive)

CONVERTER ISSUES

ERRORS:

DC: offset, gain, linearity (differential, integral)

AC: distortion (harmonic, intermodulation)

bandwidth (Full Power, Small Signal)

signal/noise ratio (quantisation: SNR 6.02xN+1.76dB, noise from active and passive components)

aperture jitter (sample&hold)

SYNCHRONISER

Analog playback devices (in most cases used equipment) supported by stabilizing circuits (frame synchronisation, time base correction) Benefit: correct colour hue and saturation

Additional signal conditioner (Format conversion, noise reduction, enhanced colour decoding)

Superior ADC-performance

ENHANCED SIGNAL EXTRACTION

Replacement of critical electronic circuits

Improved signal pickup

Example: U-Matic Recorder Replacement of “composite” signal processing by Y-C pre-amplifiers and AD-conversion; pure digital solution?)

Expensive infrastructure required!

THANK YOU!

Franz PAVUZAPhonogrammarchiv(Austrian Academy of Sciences)Liebiggasse 5A-1010 Vienna/AUSTRIAfranz.pavuza@oeaw.ac.at