App Note:
The Video Binloop as an Audio Source
Examining Alternatives

The Video Binloop is known for its performance and simplicity as a video player. It is also an audio player capable of exceptional performance. This article explains how to simplify the design of audio/video using the Video Binloop as a source of both audio and video for an attraction.

We also take a brief look at the differences between the Video Binloop, Digital Binloop and Digital Binloop HD.

Director
Alcorn McBride France

Equipment
 

Video Binloop
Digital Binloop
Digital Binloop HD

Introduction

Almost all attractions include images and sounds. In such an environment, not only should the quality of reproduction be perfect, but most of the media should be able to sync perfectly, not only among themselves but also with other elements, such as lighting or special effects. To complicate matters, it is common for a single controller to manage several areas, a preshow, main show and one or several other rooms of an exhibition or a museum.

Video Binloop Front Panel

Audio capabilities of the Video Binloop

When playing a video file, the Video Binloop reproducer cards also decode the audio associated with that video, MPEG layer I or AC-3. But these cards are also able to play, instead of video clips, "PCM" or "WAV" audio files. These formats provide optimal audio quality, because they are uncompressed. This means that one Video Binloop can provide all the audio and video needs of a ride.

A single Video Binloop provides up to 32 uncompressed audio channels (16 reproducer cards). These channels can be configured as independent or synchronous groups. Each may respond to different controls. For example, four cards could be allocated to the main show while others correspond to events triggered by visitors in the post-show.

Video Reproducer Card

Why not be content with audio encoded with the video?

The audio encoded with a video file is in MPEG or AC-3 formats. In both cases, processing is performed at the time of encoding so that the resulting file is as small as possible, trying to preserve audio quality. In most cases, the final file size is compressed by a factor of ten. While this is an amazing feat, even a non-expert ear can easily identify the compression artifacts this produces. In dedicated applications, storage is generally not a problem, especially since the duration of the media is often only a few minutes. For this reason we recommend, whenever possible, using PCM (uncompressed) files.

Independent channels in place of AC-3

Early efforts to reduce the amount of data from a multi-channel soundtrack to go back ninety years. Since that time, ORC, Dolby, DTS and Sony have developed techniques such as the 6-channel of digital audio common in cinema. It was natural that these same technologies would be used for DVD video, where storage space is also at a premium.
As designers of attractions, our approach is different: we want to offer our visitors the best possible audio quality from the source. To do this, we use as many cards as there are pairs of audio, for example 3 in the case of a "5.1" system. Besides the spectacular increase in quality, this approach avoids the needs for decoders, and completely eliminates the encoding step during production. Finally, it is very easy to have multiple versions of the soundtrack, for example in different languages, or even replace audio files without affecting the video.

Choice of professional output formats

On the hardware side, the Video Binloop also offers several audio output choices, including unbalanced, balanced, AES/EBU (or S/PDIF). It is also possible to equip the cage with a CobraNet card that is capable of distributing 32 audio channels of a Binloop on a single Cat 5 cable. Depending on the nature of downstream processing, this approach can be quite economical, because of the simplification of interconnect wiring.

Video Binloop Rear Panel

Optimize systems by using a single reproducer for two mono channels

Each card Binloop Video can play a stereo file. Several pairs can be grouped together to form a multi channels soundtrack for an associated video card. But it is also possible to load cards with mono sounds. In this case, each reproducer card behaves like two independent players: it is possible to start or stop sound on one channel without affecting the operation of the other. For example, four cards are enough to manage eight different sounds triggered by visitors to a museum. No hardware configuration is necessary. The extension used by the file tells the system whether it is a video file, stereo audio or mono audio.

Configure groups

Groups are sets of Binloop cards that behave as a single multi-channel player. For example, if cards 1, 2 and 3 are associated with group 1, they will respond to a single command to group 1. The Video Binloop allows cards to belong to several groups. For example, all the cards in a system might belong to a group used to broadcast alarm messages.

Working with files

The Video Binloop can read “WAV” files with a sampling frequency up to 48KHz and a resolution of 16 bits. These files have a WAV extension, and are named in a DOS format using SND as header, for example SND00001.WAV. Mono files are named with an SND extension.

Synchronize multiple Binloops

Several Binloops in the same attraction (or even a mix of Video Binloops and Digital Binloop HDs) can easily be synchronized. To accomplish this, they should share the same video sync signal, either from one of the Binloops or an external sync generator. The Binloops must receive commands from a Show Controller connected to the same sync signal. Our Show Controllers have a BNC input for this purpose, and can send commands to multiple Binloops, all on the same frame.

It is also possible to use one of Binloops as a time code generator, and the others as slaves. In this cases, the synchronization between Binloops is exactly the same as that between cards in one cage.

Segue smoothly

Like the video, the audio played on a Video Binloop responds instantly to commands sent by the Show Controller, always in perfect synchronicity. In particular, it is possible to seamlessly join files end to end, or to loop them, with no audible splice.

Digital Binloop HD

Audio with the Digital Binloop HD

The Digital Binloop HD can accommodate a mixture of SD cards and HD cards. It is therefore possible to associate one or more HD channels with as many audio channels as you want. Up to 8 cards can be installed in a Binloop HD cage. Of course it is also possible to synchronize several Binloops if more channels are needed. A good example of this type of application is the 3D installation at Cerza Zoo, in which a mixture of HD and audio reproducers are installed in a single Digital Binloop HD.

Digital Binloop

Video Binloop vs. Digital Binloop

The Video Binloop and Digital Binloop products are very similar. They are mechanically identical and offer the same functions. However, unlike the Video Binloop, the Digital Binloop can be equipped with Repro24 cards. These cards offer high-performance audio, capable of reading 24 bit files with a sampling frequency of 96KHz. The Digital Binloop is used in facilities where the audio quality can not afford any compromise.

In Summary

Taking into account the simplicity and the flexibility it provides, using a Video Binloop for audio playback is economical and elegant. This approach makes attractions easier to program and operate, and more reliable, with the best quality of video and audio.





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