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high def mp4 render for devices with low quality video cards?
I have been having trouble with some of my Vegas 10 renders because of the system I am outputting the final product to. See, we have a network of digital signs, and each TV has its own computer dedicated to it. These TVs are 42″ HDTVs capable of a full 1920×1080 picture. The issue is that SOME of the computers hooked to these TVs have terrible video cards or processors, and I haven’t found a way to render my mp4s without the playback being just awful: stuttering, freezing, you name it. My footage is full 1920×1080 XDCAM stuff, and while I am ok with tamping down to 1280×720 for the video, I haven’t found a bit rate or setting yet that seems to work on these ‘weakest link’ boxes. I have tried using MainConcept, 1280×720 with the bit rate screwed down to 2.5Mbps (which looks godawful with pixelation), and I have even tried doing this with the SonyAVC codec. (which I haven’t tested yet on the box but the render is just as pixelated because of the stupid low bitrate). I don’t have licensing to render in DivX, and because we want an end-user of our software to be able to render easily using their own computer, we want to stick with wmv and mp4 (wmv tends to look bad too). Any suggestions on settings I might try?
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4 Replies
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[Heather Walters] ” I have tried using MainConcept, 1280×720 with the bit rate screwed down to 2.5Mbps (which looks godawful with pixelation), and I have even tried doing this with the SonyAVC codec. (which I haven’t tested yet on the box but the render is just as pixelated because of the stupid low bitrate).”
Unfortunately there is no answer for what you want to do. You’ve already used the format that can give you high quality HD with low bit-rate (AVC/H.264) and the computers can’t handle it so you have a hardware problem on your hands. There is no way an old under-powered PC is going to handle HD regardless of how big an HD TV you attach to it.
My question to use is, “what has changed?” What format were these PC’s with HD TV’s intended to play? Use that format instead. Someone put these systems together with a format in mind. It sounds like that’s the only format that you should be using.
I’m gonna guess that DVD quality MPEG2 is the only thing that’s going to give you both quality and performance but it won’t be HD quality because the hardware can’t handle HD. High quality SD may look better than low quality HD in this case.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
*Sigh*. I can get a 720p video if I use wmv (tho in the past, when I rendered it with audio, but removed audio tracks the wmvs stuttered very badly during shot transitions). I will try 480p mp4 and see if the hardware chokes. It shouldn’t, as it’s only SD and the bit rate is around 2Mbps.
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In general, you’re going to need at least a decent dual-core processor — and pretty much of all of it — for camcorder-class AVC playback. The best place to start isn’t messing with bitrate, since that’s not your problem: your TV-PCs almost certainly have fast enough HDDs (assuming you’re not trying to do this all over a network or something).
First thing, try lowering the complexity of the AVC. Try MainConcept rather than Sony AVC. MainConcept allows you to render high definition in the AVC Baseline profile, which is simpler to decode (and, simply put, I have found it decodes better on low-power devices, like tablets, than Sony, for whatever reasons). You might experiment around with “Tablet”, “iPhone”, and other settings designed for lower power devices.
If your TV-PCs have GPUs (unlikely, but check), you want those helping the decode. This is easy if you’re running Windows 7, since the Microsoft AVC CODEC (built-in) uses the DXVA 2.0 API for GPU-enhanced decoding.
Another possibility is to render out to a higher quality HD format (high spec MPEG-2, camera-quality AVC, whatever) and use a more programmable encoder, such as x264 (TMPGenc, Handbrake). With enough control over the AVC format, you can make decoding much simpler, by eliminating B-Frames or even going all the way to AVC-Intra. This will also increase the size of the file needed to keep the quality the same, which is an issue if you’re using networks, but no big deal on an HDD.
-Dave
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Dave, those are good suggestions. Unfortunately I have no GPU decoding available, but the Handbrake suggestion in particular may be what I need. Thank you for the advice!
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