Resolutions
-
Voici mis à l'échelle 1:3 un aperçu des résolutions les plus courantes.
-
The biggest qualitative leap is between PAL (or SD, Standard Definition) and HD. The smallest qualitative leap is between 2K and HD (only 6% more resolution).
DCP
-
DCP (Digital Cinema Package or digital cinema) is the digital version of the 35mm print: this is the format that all the multiplexes and a growing number of small cinemas rely on.
-
A DCP is a collection of digital files used to store a film's information. It can be transported on a USB key (trailers ...), a hard drive, internet, etc ...
- The images are encoded in JPEG-2000: this is a very efficient compression algorithm, which can make the image lighter without losing details visible to the naked eye.
- A DCP is relatively small: about 300 GB for a feature film, less than 100 GB for a short movie.
- quality
10
- reliability
10
- flexibility
07
- widespread in big cinemas
09
- widespread in small cinemas
02
Benefits
- Exeptionnal quality
- Robustness: the whole DCP chain is very solid, the cinemas equipped to read DCPs are likely to be carefully calibrated
- Reproducible at a low cost: to copy a non-encrypted DCP, simply copy the DCP folder from one medium to another (eg.: a hard drive to a second hard drive).
- Subtitling: it is possible to add subtitles to a DCP without any re-encoding
Disadvantages
- Plurality of norms: the DCI (Digital Cinema Initiative), used by Hollywood studios, led to the Interop standard, a very rigid in terms of rates and resolutions. SMPTE standards are very recent (2010) and have widened standards by including the introduction of video frame rates (25, 50 frames per second, etc. ...). Not all DCP servers have been updated, and they do not all necessarily bear the 25 frames per second.
En pratique, les serveurs DCP rencontrés par Charbon, de Belgique, de France, d'Allemagne et de Norvège, XDC, Barco, et Doremi (qui représentent la grosse majorité des serveurs DCP d'Europe), supportent parfaitement le 25 images par seconde, en plus du 24.
Par contre, les serveurs Qube ne supportent eux que le 24 images par secondes.
- Support du sous-titrage : les normes de sous-titrage sont elles aussi passées de 'Interop' à 'Smpte' et le support de telle ou telle norme n'est pas garanti. Aujourd'hui, le seul moyen d'être sûr à 100% que les sous-titres ne poseront pas problème est de tester le DCP dans la salle où il sera diffusé, ou de 'brûler' (intégrer) les sous-titres à l'image (ce qui nécessite de refaire tout le travail d'encodage).
- Encryption: The DCP can be encrypted, so as to be readable only by a particular DCP server at a given time. One then needs the 'key' to the encryption (KDM, Key Delivery Message) which can sometimes be a problem when errors slip into a serial number, in a version of subtitling, etc ...
35mm
-
Despite a demise announced years ago, film is still very much alive, and always brings its unique look.
- quality
10
- reliability
10
- flexibility
01
- widespread in big cinemas
10
- widespread in small cinemas
09
Benefits
- Grain, dynamic, contrast, color, fragility ...
- Universal
Disadvantages
- Spoils: unlike a digital medium, the film deteriorates with each projection
- Expensive to reproduce
- Expensive to make
- Heavy to carry
Blu-Ray
-
It is a revolution: for the first time in the history of cinema, the public can access a medium whose's quality almost equates the work achieved in post production. VHS and DVD brought big changes, but they were poor quality medias compared to the digital masters or film.
-
Le Blu-Ray à la fois le meilleur rapport qualité prix, et le support le plus susceptible de poser problèmes en projection (voir partie Inconvénients).
- quality
08
- reliability
03
- flexibility
09
- widespread in big cinemas
05
- widespread in small cinemas
07
Benefits
- Quality: close to the master, high definition, high fidelity
Lors de la deuxième projection de Screening Formats, les spectateurs-invités présents ont constaté l'étonnante absence de différences entre la HDCAM et le Blu-ray préparés par Charbon
- Reproducible at a low cost
- Can be watched with or without subtitles
- support du son surround (5.1, 7.1)
- Accessible to small cinemas (but equipped with a HD projector). For a cinema with a low-definition projector (SD, Standard Definition), it is preferable to encode a special Blu-Ray SD than to let the Blu-ray player downconvert
Disadvantages
- délicat à projeter : le Blu-Ray contient des dispositifs de projection anti-copie (HDCP). Il est ainsi impossible pour les projectionnistes de l'intégrer numériquement à leur circuit vidéo normal.
Pour supporter beaucoup de formats, de cadences et de supports différents, la plupart des salles de cinéma et de festivals sont équipées d'appareils destinés à modifier le signal, convertir les formats, passer d'un cadre à l'autre, supprimer l'effet trapèze... Ces appareils ne sont généralement pas compatibles avec la sortie HDMI des lecteurs Blu-Ray.
Beaucoup de salles utilisent donc un signal analogique composante. Ce signal est obtenu :
- soit depuis le lecteur Blu-Ray lui-même (mais sous la pression des majors, les lecteurs les plus récents refusent d'envoyer un signal HD en analogique).
- soit en utilisant un convertisseur hdmi/analogique du type HdFury
- 24p : le 24 images par secondes, cadence habituelle du cinéma, est supporté par le Blu-ray, mais
- seulement après avoir bien spécfiquement réglé le lecteur Blu-Ray pour envoyer le 24 images comme du 24 images (par défaut beaucoup de lecteurs enverront du 25 images, ce qui donnera des saccades dans les mouvements)
- seulement en HDMI : le 24 images par seconde analogique n'existe pas. Il faut donc impérativement que le lecteur Blu-Ray et le projecteur soient reliés en HDMI
- Certains projecteurs de cinéma sont spécifiquement conçus pour ne pas supporter le signal HDMI d'un Blu-Ray, justement pour éviter que les exploitants projettent des disques trouvés dans le commerce plutôt qu'obtenus au prix fort chez le distributeur.
- Fragile: Blu-Ray has exactly the same appearance as a DVD or a CD. It therefore shares the same weaknesses: easy to scratch, break and gather dust.
- HDMI : la seule sortie numérique d'un lecteur Blu-ray est en général du HDMI. C'est un format grand public plutôt que professionnel, relativement peu courant sur les projecteurs de salle de cinéma, et qui supporte mal les longues distances (plus de quelques mètres), contrairement au SDI.
- son surround : la plupart des lecteurs Blu-ray ont une sortie stéréo analogique, et envoient le son surround via la sortie HDMI. Il faut donc un système pour extraire le son multi-cannal du HDMI et l'envoyer au système d'écoute. C'est un appareil courant dans les Home-Cinema, plus rares dans les salles obscures.
- En pratique : tous ces inconvénients font du Blu-Ray le support le plus susceptible de poser problèmes en projection. Si donc le choix se présente entre envoyer un DCP et un Blu-Ray à une salle inconnue, le DCP est un choix beaucoup plus sûr.
Ceci dit, les seuls problèmes jamais survenus avec des Blu-Ray sortis de Charbon-Studio se sont produits dans des salles qui n'avaient pas l'habitude de projeter correctement des Blu-Ray.
- Nécessite un mastering spécial pour obtenir la meilleure qualité possible, surtout pour les masters provenant de sources difficiles (ex. : S16mm pour le grain, Red pour le banding, etc...)
HDCAM
-
HDCAM, introduced by Sony in the 90's is a HD recorder. It has become a standard in the distribution and conservation of films in television and major film festival.
-
Its supremacy is now challenged by the DCP, the Blu-ray, and digital PAD MXF.
- quality
08
- reliability
09
- flexibility
04
- widespread in big cinemas
08
- widespread in small cinemas
04
Benefits
- Quality: close to the master, high definition, high fidelity
- Robustness: the tape and the recorder are very strong. The VTR can send an SDI signal, widely used by professionals as opposed to HDMI, used by the general public. The SDI signal can be transmitted without loss and without drop over long distances. Large festivals, most post-production studios and telivisions use SDI.
Disadvantages
- Quite expensive to reproduce
- Resolution: it is a smaller version of the HD signal 1920x1080 : only 1440x1080. Problems may arise, most notably on sharp diagonals.
- The cost of the VTR makes it exclusively available to television networks and wealthy structures.
HDCAM-SR
-
The higher-end Sony VTRs. This is a broadcast format reserved for larger film festivals.
- quality
10
- reliability
10
- flexibility
04
- widespread in big cinemas
05
- widespread in small cinemas
00
Benefits
- Quality: very close to the master, high definition, high fidelity. The colour depth and the full definition of the image are preserved.
- Robustness: the tape and the recorder are very strong. The VTR can send an SDI signal, widely used by professionals as opposed to HDMI, used by the general public. The SDI signal can be transmitted without loss and without drop over long distances. Large festivals, most post-production studios and telivisions use SDI.
Disadvantages
- Expensive to reproduce.
- Very expensive to broadcast.
HDV
-
The cheapest and the worst of HD tape formats. HDV is less interesting as a broadcasting medium since the Blu-Ray is accessible.
- quality
05
- reliability
04
- flexibility
04
- widespread in big cinemas
01
- widespread in small cinemas
05
Benefits
- High definition (like the hdcam, 1440x1080)
- Inexpensive to purchase so accessible for small screening venues
Disadvantages
- The image is highly compressed, which can be noticed in areas with solid colours, frames with many details and or shots with a lot of movement.
- Fragile media, prone to drops (small freezes or squares that appears on the image)
- Often wired to analog rather than digital
Digibeta
-
Beta-digit (or Digital Betacam) has emerged as the standard everywhere. Just as the HDCAM it's a digital video recorder made by Sony in the 90's. But unlike the HDCAM, it only works in SD.
- quality
04
- reliability
09
- flexibility
04
- widespread in big cinemas
10
- widespread in small cinemas
08
Benefits
- The highest quality of standard definition.
- Robustness: the tape and recorder are very strong. Like hdcam, beta-digit can send the signal to SDI
- Fairly widespread, at least more than the HDCAM as it's significantly less expensive
Disadvantages
- Standard definition only: 400 000 pixels (instead of 2 million pixels in HD)
- Quite expensive to reproduce
BetaSP
- Beta-sp (or Betacam), appeared in the 80's and is still in use today as it is a widespread media.
-
- quality
03
- reliability
04
- flexibility
04
- widespread in big cinemas
10
- widespread in small cinemas
10
Benefits
- Cheap, widespread
- Robust despite its age
Disadvantages
- Standard definition only, analog only
- If poorly maintained, the Betacam SP equipment can lead to a poor screening
- Quite expensive to reproduce
DV
-
The DV (Digital Video, variants: DVCAM, miniDV) is the standard that has made digital video available. It is now a little older, but still better than the DVD.
- For a better screening quality it is best to use a DV recorder rather than a camera. The recorder is more robust and well wired.
- There is no difference in quality between DV and DVCAM. DVCAM is just a little more robust because it uses more tape to store videos.
- quality
03
- reliability
05
- flexibility
04
- widespread in big cinemas
02
- widespread in small cinemas
07
Benefits
- Cheap, widespread
- Better quality than the DVD
Disadvantages
- Only in standard definition, almost allways wired in analog
DVD
- The most common standard, used in all productions, is also one of the least trustworthy standards.
- quality
02
- reliability
04
- flexibility
10
- widespread in big cinemas
07
- widespread in small cinemas
10
Benefits
- Cheap and universally used
- Easy to view
Disadvantages
- Standard definition only: 400 000 pixels (instead of 2 million pixels in HD)
- Often wired in analog
- Extremely high compression of the image
- Requires mastering to get the best quality possible
Editing suite
- In most cases a Mac Pro with a video card (eg, Blackmagic, AJA), that sends a signal to SDI, HDMI or Component to the projector.
- The use of a video card is required. It is possible to use USB video cards to send the SDI signal, making it possible to use laptop computers (eg MacBook Pro with a Matrox MXO or laptop with a Blackmagic Intensity UltraStudio or Shuttle)
- Sans carte vidéo, on revient dans le domaine des Computer Media, beaucoup plus problématiques.
- A technique widely used in film schools and some festivals.
- quality
09
- reliability
04
- flexibility
09
- widespread in big cinemas
02
- widespread in small cinemas
03
Benefits
- High quality: an editing station can directly read the master avi or quicktime or mxf
- Much better and cheaper than HDCAM
- It's inexpensive to screen a film in a room equiped with an editing station: just copy the master on the station.
- Flexible: it's easy to view a particular subtitle track or to choose a particular version of the soundtrack or of the audio
Disadvantages
- Hard to implement if the room is not already equipped with an editing workstation
- Is as reliable as the computer. But computers are more likely to interrupt a screening than VTRs are.
