Draft:INA-Saphir

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  • Comment: Is there any coverage of this in reliable secondary sources? It seems all the sources currently cited are close and primary, incl. papers co-/authored by the inventor. We need to see that others have covered the subject extensively. -- DoubleGrazing (talk) 08:02, 12 March 2022 (UTC)

INA-Saphir is a process that optically retrieves sound from a disc phonograph record. It was initiated by INA in 2002.

Introduction[edit]

Disc phonograph record, invented before 1889 by Emile_Berliner, were the main recording and playback medium from the extinction of Phonograph_cylinder (1929) to the generalization of Tape_recorder (early 1950s). The easiest way of recovering the sound contents of a disc record is usually playing it on a turntable using a physical stylus, but a number of conditions may render the record unplayable physically. The most difficult records are often unique lacquer recordings, broken, or with cracked or delaminating lacquer.[1] Optical playback is often the only solution for recovering the sound of those damaged records.

History[edit]

The INA-Saphir process was imagined in 2002 by Louis Laborelli in INA, patented in 2004[2], and described in articles in 2007.[3][4]

The project was developed as a collaboration between INA and Indeep between 2007 and 2011.[5][6][7][8] Since then, the project was developed principally in INA under the Saphir or INA-Saphir name.

The first recoveries of otherwise unplayable records were made in 2016.[9]

The first external uses of the system were in March 2019 where a number of records were scanned in Montreuil for Gecko, October-November 2019 in Hilversum where 36 sides were scanned[10][11] for the participants to the 50th IASA conference[12] and JTS 2019[13] hosted by Beeld en Geluid, and in 2021 in Montreuil again, where 51 disc sides were scanned and decoded by Gecko for VRT. [14][15][16]

Principle[edit]

Scanning process[edit]

As the ELP_Japan Laser_turntable system, INA-Saphir uses the reflection of light to measure the slope of the groove with respect to the tangential direction. This allows the highest frequencies to be recovered.[17]

A specifically-designed condenser casts rays with varying colours onto a 2.5x2mm region of the record, at 45 degrees, i.e. perpendicularly to the groove walls. Rays reflected are collected through a doublet lens pair and focused on a board 2D camera sensor.[17]

The full active surface of the record is scanned as 40 to 70 rings of 1250 overlapping colour pictures, stored as raw files.[17]

Image Processing and Sound Extraction[edit]

The Saphir Play software tool extracts from each picture the successive track segments, and converts the colour to a cutter velocity measurement i.e. an audio signal value.[17]

The resulting segments are stored on a map of the disc side, and overlapping segments are fused into fragments.

The resulting fragments are connected in the correct order for generating the sequence of audio samples. The audio samples are stored in a wav audio file.

Broken and Cracked Records[edit]

When the scanned record is broken or cracked, or when pieces are missing, the correct order for playing the audio fragments has to be decided.[17] This is done using a shortest path solver, penalising long jumps, but with reward (negative costs) for using as much as possible of the available fragments.

Operator involvement is usually necessary at this step, to add constraints that will help :

  • guiding the preferred connections
  • cutting fragments at cracks crossings
  • solving the problem faster

System quality[edit]

The audio quality obtained from the INA-Saphir system is quite dependent on the condition of the record. In the best conditions, on a pristine vinyl 78rpm record, THD+N was measured at 3.1% (-30dB) in the 20Hz–20kHz band.[17]

The quality is usually worse than obtained from a proper mechanical stylus playback. Therefore the main usage of the INA-Saphir system is considered to be the preservation of records that cannot be played mechanically.[1][17][18][19]

Advantages and disadvantages[edit]

The approach used by INA-Saphir provides a set of advantages over conventional or optical disc records playback: [17]

  • Can scan and recover records in very poor condition
  • Scans are usually made under a 3mm glass pane, that protects the record and keeps it flat
  • Up to the highest useful frequencies can be recovered (20kHz at 78rpm)
  • Compact: scanner size is smaller than a conventional disc turntable
  • Can skip over any crack/break/hole/corruption
  • Large range of disc records playability, including lateral and vertical cut records [10][19]

Disadvantages of the system: [17]

  • Slow : on average 30min per scan, 1 hour for decoding, up to several hours of effort for reconstruction of very damaged records
  • Intermittent signal acquisition can generate in artefacts that have to be filtered out
  • Signal quality worse than conventional playback
  • Only applicable to disc recordings

Recovered sample files[edit]

First recording by fado singer Maria_Teresa_de_Noronha: Fado de Mouraria (1939). Aluminum-based lacquer disc, numerous fine cracks. [1]

From INA collections, Set W1425, "Voici ma carte Monsieur : L'existentialisme Pictural !", 10 minutes live recording by Pierre_Sabbagh of the first French post-war (spade) duel, 1946. Zinc-base lacquer disc, severely degraded, very brittle lacquer, peeling off. [2]

From CNRS Centre for Research in Ethnomusicology collections, ethno-musicological recordings by Maurice Leenhardt in New Caledonia (1939). Zinc-based lacquer discs, 25cm, severely damaged (multiple delaminated lacquer flakes, exudates). [3]

From VRT collections, first 65 seconds of "Comité Tegen Het Alcoholisme Antwerpen" in [4], and "Peter Benoit - Reprise Van Scherzo Uit Strijkkwartet Op.10" [5], earliest known VRT recording of string quartet Op. 10 by composer Peter_Benoit.[16]

See also[edit]

The following other optical transfer techniques for analogue audio records are in exploitation (2022):

  • Laser turntable: analogue optical player for disc records in good condition
  • IRENE (Image, Reconstruct, Erase Noise, Etc.) technology: US technology for optical playback of cylinder and disc records[20][18]
  • VisualAudio: Swiss technology for photography and optical playback of disc records[21][18]

References[edit]

  1. ^ a b Rochat, Rebecca (2018). Typology guide. Lacquer disc collections of Radio-Lausanne and Radio-Genève (PDF). FONSART - Fondation pour la sauvegarde du patrimoine audiovisuel de la Radio Télévision Suisse.
  2. ^ FR2874280, Laborelli, Louis, "Equipement pour la lecture optique des disques phonographiques analogiques"  US7660208B2, Laborelli, Louis, "Equipment for the optical playback of analog phonographic records"  EP1626402, Laborelli, Louis, "Device for optically reading analogical phonographic disks"  DE602005002890T2, Laborelli, Louis, "Anordnung zum optischen Auslesen analoger phonographischer Tonträger" 
  3. ^ Laborelli, Louis; Chenot, Jean-Hugues; Perrier, Alain (2007). Non contact Phonographic disks digitisation using structured colour illumination. AES 122nd Convention. Vienna (AT).
  4. ^ Laborelli, Louis; Chenot, Jean-Hugues (2007). Dust Detection by Colour Analysis in an Optical of Phonographic Disks Digitisation. ICIP 2007 (IEEE International Conference on Image Processing. San Antonio (USA). doi:10.1109/ICIP.2007.4379945.
  5. ^ "PrestoSpace Deliverable D4.3 PPB3 Contactless playback tool for audio disks (pdf)" (PDF). 31 January 2007. Archived (PDF) from the original on 2012-05-23. Retrieved 2022-02-04.
  6. ^ Wanègue, Jean-José (October 2007). "L'image numérique au service de la numérisation des anciens disques" [The digital image serving the digitization of old disks]. La Revue du Son et du Home Cinéma [The Sound and Home Cinema Magazine] (in French). No. 322. pp. 100–104. Declercq, Brecht (November 2011). "The digital image serving the digitization of old disks - Translation". arsclist (Mailing list).
  7. ^ Sené, Xavier (December 2008). "New Optical Sound Reading Systems" (PDF). International Preservation News. No. 46. IFLA. pp. 22–23.
  8. ^ Wanègue, Jean-José (May 2009). "Les urnes de l'Opéra". Realisason (in French). No. 56. pp. 62–65. p. 65: Un oiseau rebelle recouvre sa liberté grace à l'INA [A rebel bird recovers its liberty thanks to INA]
  9. ^ "Saphir web site: Playback Examples".
  10. ^ a b Chenot, Jean-Hugues; Laborelli, Louis; Noiré, Jean-Étienne (2019). Saphir: Digitizing broken and cracked or delaminated lacquer 78 rpm records using a desktop optical scanner. JTS (Joint Technical Symposium of CCAAA). Hilversum (NL).
  11. ^ "Novyfonograf report: IASA & JTS 2019". October 15, 2019.
  12. ^ "IASA 2019 - 50th Annual Conference". September 30 – October 3, 2019.
  13. ^ "JTS (Joint Technical Symposium) 2019". October 3–5, 2019.
  14. ^ "Gecko preserves VRT lacquer discs using Saphir optical system". Gecko. October 26, 2021.
  15. ^ "Optical digitisation of broken records". Meemoo. October 26, 2021.
  16. ^ a b "SIRDUKE: Erfgoed van VRT Archief gered door pioniersproject voor lakplaten" (in Dutch). VRT. October 26, 2021. "Unique sound heritage saved by VRT pioneering project". VRT. October 27, 2021.
  17. ^ a b c d e f g h i Chenot, Jean-Hugues; Laborelli, Louis; Noiré, Jean-Étienne (August 2018). "Saphir: Optical Playback of Damaged and Delaminated Analogue Audio Disc Records". ACM Journal on Computing and Cultural Heritage (JOCCH). 11, 3: 14.1–29. doi:10.1145/3183505. S2CID 240171723.
  18. ^ a b c Shimoda, Yuri (2020). "Optical Transfer Technologies for Radio Transcription Discs" (PDF). Journal of Archival Organization. 17:1-2 (1–2): 125–143. doi:10.1080/15332748.2020.1788313. S2CID 221380605.
  19. ^ a b Chenot, Jean-Hugues; Noiré, Jean-Étienne (2023). Challenges in Optical Recovery of Otherwise Unplayable Analogue Audio Disc Records (PDF). AES International Archiving & Preservation Conference. Culpeper (USA).
  20. ^ Fadeyev, Vitaliy; Haber, Carl (2003). "Reconstruction of Mechanically Recorded Sound by Image Processing" (PDF). Journal of the Audio Engineering Society (JAES). 51, 12: 1172–1185.
  21. ^ Johnsen, Ottar; Bapst, Frédéric; Seydoux, Lionel (2008). Sound extraction of delackered records. AES 125th Convention. San Francisco (USA).

External links[edit]

Wikimedia Commons has media related to INA-Saphir.

Category:Mass digitization Category:Digital preservation

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