Quote:
Originally Posted by MrNewYears /forum/post/0
I do notice some pixellation watching sports via component. With DVI/HDMI there was none and I suspect it was because there was no compression/decompression going on.
Just in passing, I don't believe that the visual symptoms of picture degradation you're describing can be attributed to what would be described as "compression/decompression going on". In all honesty, I think it's more the normal expected difference from one sporting event to another based on factors such as HD cameras, encoders being used, channel/network you're watching, importance of the event itself, etc. These would affect overall broadcast and picture quality, including likelihood of blocking or pixelization resulting from motion.
What happens in the STB/DVR when putting out its component video version of what goes out "digital direct" via DVI/HDMI is the result of digital-to-analog conversion, not compression/decompression. What is put out on component video is simply the analog version of the digital datastream, fed to your projector using the RGB analog method. There is no further compression of the source content that takes place at this step. Once digital content (however it was produced) is delivered to your STB/DVR that's what is worked with.
And there it is dealt with by your projector as best as it can... including being converted back to digital for actual display. But there is no decompression taking place in your display device, either from its analog or digital inputs. What it's being sent by the STB/DVR is the fully decoded and decompressed datastream, either in digital form (gigabytes per second) or in analog component video form.
So anything you're possibly seeing in the way of slightly inferior picture is due to the results of the D/A-conversion taking place in the STB/DVR, and then the reverse A/D-conversion in your [fixed-pixel] HDTV projector. And of course none of this happens in straight digital passthrough from source to display using DVRI/HDMI... so the picture is likely a bit superior.
But it's not because of eliminating compression/decompression. Compression/encoding (and possibly re-compression by the carrier) occurs at the broadcaster/network/carrier end, and once it's done it's done. Your STB/DVR receives it that way (in its digital MPEG-2/4 form) and decodes/decompresses it. That decoded/decompressed digital stream (matching how it came from the broadcaster or network or carrier) is then either sent directly to your HDTV (via DVI/HDMI) or converted to analog for component video output.
So the poor picture quality of high-speed motion (like sports) would be caused by either the broadcaster or network or carrier, if the encoders can't keep up with the requirements of the content and either don't give it enough bitrate to handle the needs of the motion or simply "max out the hardware capabilities". You might be watching something one day that looks good, and something different on another day that doesn't... even with the a DVI/HDMI connection.
But I assure you it's not because of a component video connection that you're seeing pixelization and blocking on high-speed motion or common sports coverage (which, of course, is mostly motion).
