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Studio OnLine -

Facts & Figures

For the most part, this information has been extracted from the Studio OnLine dialog box Options, and Help files, with a little research and 'reverse engineering' thrown in. Acknowledgement also goes  to Pinnacle Engineering who provided guidance with the more esoteric aspects.

From Camcorder To Screen.....

We are now going to look at how the Video and Audio signals from your camcorder are handled by the Studio Online system. We shall examine the process of converting the analogue camcorder outputs into a digital stream, compressing and decompressing across the USB link,  recompressing and streaming data to disk, and finally creating an (edited) output file in its own compressed format, either to disk or to the Pinnacle Host site.  

Capture and Saving to Disk

The incoming composite (analogue) video signal is decoded (converted from Scanned Raster format to Digital YUV 4:2:2 data stream), and passed through a proprietary-format compressor to reduce the data-rate, suitable for USB transmission. The format of the compression algorithm is MJPEG-like, and uses only 'I' frames; that is, each frame is compressed separately, to maintain consistent quality, and reduce 'motion' effects. These processes are handled by a fast microprocessor and dedicated hardware within the module at the end of the Capture cable.

At the other end of the cable (PC), the USB data stream is decompressed in the  USB driver (an especially fast software algorithm that is very CPU-efficient, and makes full use of Pentium MMX capabilities), then recompressed using Pinnacle's PIM1 codec into an I-Frame-Only MPEG format .avi file (now, there's an interesting concept!). 

This .avi file may be viewed using a player such as Windows Media Player, but only on machines that have Studio OnLine (SOL) installed. This is because the PIM1 codec needs to be present, which is not a standard Windows component. This is to be expected, since this codec will normally only be required during  SOL Capture and Editing sessions.

It is said by the manufacturers of the chipset, used in the Capture Module, that the video quality emerging from the USB driver is almost indistinguishable from the original analogue input image.

Audio signals, however, do not fare quite so well. This is acceptable because, in the main, most captured audio will be from your camcorder, where true high-fidelity sound is rarely available.  (Yes, modern camcorders have the ability to record HiFi sound but, unless you have provided  yourself with a 'sound crew', and the paraphernalia to exploit this fully, you will not achieve it . If you had, it is unlikely you would be editing with SOL).

Stereo Audio signals are quantised in a 16-Bit Analogue-Digital converter, sampled at 16kHz, and added to the compressed video stream before being serialised into the USB data stream. The audio is not compressed, and has a fixed serial data rate (stereo) of 512 Kbits/sec (about 1/10 of the video serial data rate).

The Make Movie Process

During the Make Movie process, as the video data is rendered it is recompressed using codecs, which will be compatible with non-SOL machines. The actual codec used will depend on the output option you choose -

Share

The rendered movie is coded in MPEG-1 format and uploaded, on-line, over the Internet, to the Pinnacle hosting website. Here it is transcoded into four streaming files - two of type Real Media, and two of type Windows Media. (Each media type has two versions - low and high bandwidth, hence the existence of four files).

AVI

This will produce VFW compatible movie files on your disk, using any codec on your system. If you are going to distribute these files to third-parties, then choose a codec (such as Cinepak or Indeo), which are available widely on standard Windows installations.

MPEG-1

This will produce smaller files than the .avi format, yet maintain high image quality. Files distributed in this format should be universally playable on any multimedia computer.

Real Media

This will produce files that are generally smaller than MPEG files, yet maintain good quality images. The format was introduced by the RealNetworks Inc. as a means of streaming real-time movies over the Internet. To view these files, you need a compatible Real Media player. This is rapidly becoming less of a problem nowadays. With so much 'encouragement'  to download (free) the Basic player from the Internet, or from magazine cover-disks, it is highly likely that your audience will already have one installed on their system. The Basic player is also included as part of the SOL installation.

Video and Audio Specifications and Options

We are now going to examine the capabilities of SOL in numerical terms (Video Standards, Image Sizes, Frame Rates, Data Rates, etc.). 

Capture

Video Standards Supported - NTSC,  PAL,  PAL-M,  PAL-N,  SECAM

Make Movie

AVI

Frame Size -  Each dimension individually  adjustable. (I have used 80x60 to 720x540)

Frame Rates - 5,  10,  15,  25,  29.97,  30   (Note - PAL 12.5 not available, but it is possible to set to 'Same as Project', so if PAL Half Frame Rate is selected in Capture, this will do it)

Codecs - Any applicable codec on your system, but cannot use 'Uncompressed' (This is a shame, because it limits Recursive Editing, such as when creating compound scenes and titles)

Audio Options - Mono/Stereo,  8/16Bit,  Sample Rates 8, 11.025, 16,  22.05,  32,  44.1,  48 ksps

MPEG-1

REAL MEDIA

These are setting options - sorry, no actual datarates available

This format is intended for Internet streaming, so this codec has the ability to adjust compression and frame rates to optimise the file for particular target audience(s). This sets it apart from the other file formats. The settings that you apply are intended to influence the way the file is optimised, rather than set specific values. 

The resulting file will be saved on your harddrive. It is up to you what you do with it then - you could fool it into producing the best quality, highest frame rate movie if you are going to watch it on your local machine or burn it to CD but, in general, for Internet or Email use, be honest about the capability of your target audience's data link. Be sensible too with the image size. If you specify the largest size, then image quality and frame rate are likely to suffer.

Two different kinds of file can be made -

One is intended for use with a Real Server. This is a service that has to be provided by your ISP or Web Host, if you have a website (not all will offer this). In a nutshell, this kind of file carries information about the range of communication rates you expect your target audiences to require. The Real Server (at your ISP or Host Site) will adjust the quality to match the speed of the link when your audience requests the video to be streamed to them.

The other is for HTTP transfer. This requires no 'server side' processing. It is a fixed rate file that is downloaded to your audience, just like any other file, from your website. The recipient's browser should recognise this as a Real Media file, and automatically launch the Real player. It is up to you to decide what speed link your audience is most likely to have. If you set this too high, then there is a good chance your movie will be viewed with huge 'gaps' in it. If you are making a Real Media file for your own local consumption, or perhaps for viewing over an Intranet or local network, then HTTP is the setting to go for, and with the highest possible link speed, frame size, and quality setting.

Video Quality Setting - This offers a trade-off between Frame Rate and Image Quality. The settings are : 

• Normal Motion
• Smoothest Motion (I am sure this and the previous should be swapped)
• Sharpest Image
• Slide Show

Slide Show offers the highest quality image, but the lowest Frame Rate. (You will find that, in general, the perceived quality will be higher if you sacrifice frame rate for sharpness, unless your movie contains a lot of high speed motion such as sports), but do not over-do it.

Frame Size - 160x120,  240x180,  320x240

Target Audience - This relates to the speed of the modem link. Starting with the slowest -

• Dial-Up Modem
• Single ISDN
• Dual ISDN
• Corporate LAN
• 256k DSL/Cable
• 384 DSL/Cable
• 512k DSL/Cable

If you are using a Real Server, then you can select any, or all, of these. For HTTP, you can select only one (the further you choose down the list, the larger the file will be)

Audio Quality - This must also be taken into account when specifying your file characteristics. If you choose a quality that is unnecessarily high, it will eat into your overall allocated data rate, and result in a lower quality image. Starting with the lowest quality  (The first three are Mono) -

• Voice Only
• Voice + Background Music
• Music
• Stereo Music

Finally, it is possible to make a Real Media file with either no video, or no audio, such is the flexibility of the ubiquitous 'media' file description.