![]() Frankly, I don't even bother with anything as low as 100 Kbps and do not expect anything approaching good quality for "normal" full-motion source content. I normally stay in the 2 Mbps to 3 Mbps range for SD (640x480 to 854x480) content. I tend to consider 768 Kbps data rates as low speed, 1.7 Mbps as low-medium, 2.5 Mbps as high-medium speed content, and anything higher than that as being SD or HD high-speed use. Oops! I interpreted the 450 to be 450 Kbps for video and 100 Kbps for audio which is as low as I would normally go when creating H.264/AAC 320x240 content for iPod Classic 5th use some years ago. The 2 speeds (450 and 100) were for high speed and low speed users. This comes in handy for the testing manual nuances and, when/if you like the test results, you can save the profile for further use by editing it to rename it using a descriptor denoting its specific use. If you create your own test profile, a window will open having the "Quality" slider under the "Video" tab. This is the one I described as having only single-pass CBR and VBR capabilities. Apple equivalent for up-to-date compression format, of course, would be an H.264/AAC file but many Windows users continue to live in the past for "compatibility" rather than moving up to more modern compression formats. ![]() Don't really like WMV either, but at least it is a better option if you have Flip4Mac installed. Totally agree with Dave here regarding AVI files. However, as previously indicated, this work flow produces a larger than the Visual Hub DivX/MP3 file I mentioned above. If you are using the MPEG Streamclip "Export to AVI" work flow, then select "Uncompressed" audio compression. I get no audio though so far when exporting to AVI. However, I would normally use Visual Hub for the conversion since it contains the a built-in DivX codec which doesn't conflict with the Perian component I keep installed in my QT component library. Mid-quality would probably target an 854x480 file at something like 1650 Kbps or a 640x360 at about 1350 Kbps. In any case, I would likely go with a DivX/MP3 if forced to create AVI content but am still not sure what connection speeds are being targeted. Not sure if you are referring to a true RTSP or "faststart" file here. ![]() I assume this should be enough information to get you started. As I did not know if your client's 550 (450 + 100) Kbps bit rate target was for the WMV content or the cached content, I suggested the initial 25 quality rating as a good starting point for your own preliminary output testing.Īs to audio bit rate targets, it is more common on the mac to use CBR encoding for which the Flip4Mac codec has a 96 Kbps 44.1 KHz pop-up option that most closes your client's target. When finished cacheing, the number will likely double in size as it switches to monitoring the partially decompressed data actually used by the QT player. The first (lower reading) is for the raw cacheing WMV data which is partially decompresses as it is cached. Be advised that when you test the file for playback, you will likely see two different data rates in the "Inspector" window. (In this case for a 320x240 target resolution, you may want to try something like a quality setting of 25 and go up or down depending on the results for your particular source file. If not, then you must use the Quality slider to "guesstimate" single pass video data rates whether creating CBR or VBR conversions. ![]() Since you did not indicate which version of Flip4Mac you purchases, I don't know if you have the option to actually set multi-pass average and peak bit rate targets. (Think of it as having a variable data rate with constant quality.)Ĥ) Fast start or streaming content always plays most smoothly if the playback data rate is kept lower than the target user's ISP average connection speed. (Think of it as having a constant data rate with variable quality.)ģ) Variable Bit Rate (VBR) encoding varies the data rate in an attempt to keep the quality more or less constant. Should I choose constant CBR or variable VBR and when I watch the export using QT it is giving me a data rate (in the show info window) that is meaningless to me.ġ) The target bit rate always varies to some degree depending on the graphic complexity of the source content.Ģ) Constant Bit Rate (CBR) encoding provides a more or less constant data rate at the expense of varying the quality dependent on the instantaneous graphic complexity of the source file. There are a lot of options for diff bit rates.
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