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ECTV FAQs 1) Why do EarthCaster streams look better than other encoders at the same data rate? 2) How do EarthCasters output so many simultaneous streams and why is that important to me? 3) Why is the signal-to-noise ratio of the original media so important? 4) What file types can I export
from EarthCaster? 10) What does de-interlacing
mean and should I use it? 11) What are the advantages
and disadvantages of using SureStream and MultiRate streams as opposed
to single rate streams? 12) My streams look darker
than the original source video. How do I correct that? 14) My audio sounds fine locally, but seems to be distorted in the stream. What to do? 15) Can I output differently
sized streams simultaneously? 20) Can I add titles, graphics
and prerecorded video and audio to a live webcast? 22) Can I automatically stream
a list of video files to create an automated web-based TV station?
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1) Why do
EarthCaster streams look better than other encoders at the same data rate?
All EarthCaster encoders
are manufactured with broadcast-quality components as opposed to hobbiest-quality.
EarthCaster's frame buffer cards are configured to capture full CCIR-601
4:2:2 broadcast resolution (720x486) from composite, component, Y-C, DV
& SDI sources. The system's processing amplifiers all the video, black level, chroma, and hue parameters to be adjusted to ideal levels via the built-in waveform monitor and vectorscope. 2) How do EarthCasters
output so many simultaneous streams? By simultaneously outputting multiple streams, EarthCaster users can configure their encoders to provide the optimum stream for a wide variety of customers without incurring the expense of additional encoders. Most streaming websites offer as least one low-bandwidth stream for their modem-based viewers and at least one high-bandwidth stream for their broadband customers. In addition, many sites offer a low and high bandwidth stream for Microsoft, Real and now even Flash formats. Consequently, streaming sites that utilize traditional encoders may be required to implement two, four, or even six separate encoders in order to provide an appropriate variety of streams. Typically, EarthCaster users can implement all necessary streams from one encoder. The same is true for transcoding tasks. EarthCasters can perform batch encoding tasks to a variety of formats and datarates automatically, dramatically reducing the labor required. 3) Why is the signal-to-noise ratio of the original media so important? Encoding algorithms work quite well if the original media is noise-free. The slightest amount of noise, however, dramatically reduces the quality of either's output stream. Noise does not encode well, under any circumstances. Consequently, it is of primary importance to send any encoder the best quality video and audio available. If you have a choice of signal formats from your source camera, switcher or VTR, always choose the format with the best S/N ratio. Use the following formats in order of preference: SDI, DV/component, Y-C, composite. 4) What file types can I encode/export from EarthCaster? In a live encoding situation (depending on the model and options), EarthCaster can encode MPEG1/2/4, WMV, RM, QT & FLV streams. 5) Can I edit or
trim clips with EarthCaster? 6) Can I archive
separate streams while live encoding without stopping the live stream? 7) Can I stream
to more than one server simultaneously and can I stream to both a Microsoft
media server and a Real media server simultaneously?? 9) Can I remotely
control an EarthCaster encoder? 10) What does de-interlacing
mean and should I use it? When video is displayed
at 60 fields per second, this interlacing technique allows NTSC video
to capture and display very smooth motion video. Streaming video, however,
is limited to 30 images per second, at best. Combining two sequential
fields into one image creates an image that may appear somewhat blurry,
if there is movement between the two images. When a stream must
be displayed at less than 30 frames per second, this blurring (exhibited
as horitontal lines around the edges of action portions in the images)
becomes quite noticable. This is an anomaly of both Real and MS streams.
To limit the distortion caused by this interlacing anomaly, one may turn on de-interlacing. This function, found in both Real and MS, eliminates one of the two fields in each frame, thus eliminating the slight blurring caused by combining two sequential fields. While de-interlacing helps to limit the distortion in high-motion scenes, it reduces the resolution by 50%. Consequently, one may notice that the overall imagery is softer and any text or graphics will appear less crisp. If you are creating Video-On-Demand (VOD) files, it is a good idea to encode a few seconds with and without de-interlacing. Check the results of each file to evaluate the motion artifacts and/or the softness of a stream to see which is the most desirable. 11) What are the advantages and disadvantages of using SureStream and MultiRate streams as opposed to single rate streams? Real and MS both offer combined-bandwidth streams called SureStream and MultiRate stream, respectively. In each case, the player/server evaluates the bandwidth of the connection and displays the highest data rate possible. In this way, a modem-based or even a broadband viewer with a slow connection receives the best possible bandwidth rather than a series of still frames. This combined-rate approach also allows a single link to be placed on a website, as opposed to one link per data rate. 12) My streams look darker than the original source video. How do I correct that? Both Real and MS streaming algoithms tend to lower the black level of their encoded streams slightly. This results in streaming media that appears darker than the original video. EarthCaster encoders address this issue by incorporating two, full-function processing amplifier circuits. The "Input Proc-Amp" allows the incoming video to be precisely adjusted to meet optimal broadcast parameters. A built-in waveform monitor and vectorscope are incorporated to aid in the adjustment of these signals. 13) I have black or discolored borders on my source video. How can I correct this anomaly? Borders are the result of vertical and horizontal blanking information that is part of all video signals. The position and size of these borders may vary slightly depending upon the video source; VTR, TBC, switcher, satellite, etc. Use the "Crop" feature to correct this anomaly.
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