Originally Posted by John Haghighi
Amir, What is the verdict for the Sony SXRD XBR2 RPTV's can we expect it to work@1080P? Don't let them forget about all of us! Here are the specs again for the VGA and what has been said about the issue:
Sony XBR2 RPTV VGA Input supports:
horiz frequency-67.5 khz
vertical frequncy-60 Hz
input does not support Sync on Green or Composite Sync
Here is what has been said about the problem:
-360 is sending Sync on Green
-The XBR2 is looking for a: 1920x1080, 60Hz Vert, 67.5kHz Hor.
-The 360 is providing: 1920x1080, 60Hz Vert, 66.9kHz
-For 1080p over VGA the TV needs 67.8hrz and the X360 outputs its 1080p signal at 66.7hrz
-MS's VGA output does not support DDC standards
If you can get that info to the right 360 team that would be great, would like to know if it's possible for them to fix the VGA output without hosing other displays...
Sure. I will pass on.
Have quite a few questions in regards to WMA-Pro as I've been able to decode it with my AV Receiver but have never used it.
Ben or Amir, in terms of WMA-Pro, can you please clarify what makes it more advanced than other common codecs?
Specifically, where does it line up it terms of fidelity comparison with Uncompressed PCM, MLP (DVD-A/Dolby TrueHD), DTS HD-MA, DD+, DTS-HD@3Mbps, DTS-HD@1.5Mbps, DD, DTS, AIFF, WAV, Apple lossless? (Please point out if your rankings are factual based on spectrum analysis or personal from experience)
WMA Pro algorithm is not public so I cannot talk about the details in the algorithm. In general however, our design goal was 2X more efficiency than DD/DTS. In double blind tests at 760 kbps, we matched the performance of DTS at 1.5 mbit/sec for example (5.1).
WMA Pro supports both lossy and lossless encoding. It will dynamically switch between the two as necessary but you can force it to encode strictly in lossless mode.
Like VC-1, WMA-Pro uses more advanced techniques which require more MIPS, but generate better efficiency.
Is the WMA-Pro we will see on the 360 an option to convert audio to over optical the same "Windows Media Lossless" version we see as an option to burn with under the windows media player?
Yes, and no. The lossless mode in WMP is indeed a subset of WMA Pro algorithm. WMA Pro however, goes beyond that, with support for 7.1 channels and 24-bit, 96khz support and lossy/lossless encoding.
If it is, I would like to know why it's called lossless, and what the differences are between wma, wma variable, and wma lossless (are these all version 9)?
There are two codecs in play here. Standard WMA and a different lossless codec. Encoding modes are as follows:
WMA. Standard CBR mode. You set the bit rate, the codec attempts to match it by varying quality. Good for streaming content on the web where you want a constant data rate.
WMA VBR. You set the quality, the codec picks the data rate. Since the quality stays constant (according to the codec's internal measurement), your ear will find it much harder to detect distortion. Note that if you set the quality to 100, you are telling the codec to reproduce the quality of the source. The output is still lossy, but should match the quality of the input. This is called perceptual lossy encoding. It averages 4:1 compression whereas true lossless gets 2:1. The difference in quality is very small here but of course, the cost in storage and bandwidth is not. Go ahead and test this and compare it to WMA Lossless. Also note that many portable audio players can handle WMA/WMA VBR but not lossless.
WMA Lossless. Per above, this is a subset of WMA Pro and other than name, has nothing to do with WMA. It is a true lossless codec like MLP/TrueHD. Its data rate by definition is variable with average in 2:1 range although this is content dependent. My recommendation for people ripping their music is to use this codec given the low cost of storage these days.
Specifically what bitrate can we expect with each variation, and is the lossless bit for bit the same as the original source or is it perceptively lossless (kinda of like what Ben believes DD+ achieves for Movie soundtracks)?
WMA Lossless is bit by bit identical. But please keep in mind that reading a CD is a non-deterministic process in data mode. That is, WMA Lossless does indeed reproduce every bit the media player feeds it. But whether the media player always reads every bit correctly is up for grabs (regardless of whose media player we are talking about). Using the right DVD player helps a lot here.
WMA at 128kbps achieves a level of quality that 95% of the people think is the same as the source. Once you get to 256kbps, this number is probably at 99%.
WMA VBR at Q100 is very, very transparent. Data rates using 4:1 number is in the 300-400Kbps range. With all the codec testing I have done over the years, I can still pick it from the original on my expensive equipment but most people will not be able to do the same (I know what to look for).
What is the max bit-rate of WMA-Pro, what's the ceiling of dimishing returns as far as improving results, and how is it more of an advanced audio codec than MLP?
I don't believe we have a limit to the bit rate for WMA Pro (there is probably one but it is high enough to not matter). Per above, at 750kbps and higher, its quality is excellent. So going past this point you are in dimishing return domain (for 5.1, 24-bit/48khz). In its lossless mode, from what I recall, we outperform MLP a bit but the difference is small (and of course, the quality identical).
One small note here: all the encoders in 360 are running in real-time. As such, their performance is somewhat different than off-line software encoder which can take their time encoding.
Is it more advanced because of the way it throws out information an compresses data to give the perception of lossless?
Again, I can't disclose the algorithm. But suffice it to say, we use more advanced techniques to code the audio which while more CPU intensive, produce better efficiency (and better quality at the same data rate).