| Blog | # of Comments |
|---|---|
| Engadget | 2 Comments |
| Engadget HD | 4 Comments |
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Let's go down the list:
1. To say that 28Mbit is the minimum because of a compression ratio of 107:1 just demonstrates pure and utter ignorance of how digital codecs work.
2. DVD movies are not '4-8Mbits'. The maximum standard transport bitrate is 9.8Mbit. The disc maximum bitrate is 11Mbit with a 1Mbit overhead to allow for device buffer compensation.
3. Over the air is not 19.38Mbits. ATSC is 19.393Mbits. DVB-T with QAM64 weighs in at 24Mbit (the author was almost right - just didn't know what country, transport, and modulation standard he was talking about). And then you factor in the other elementary streams in the transport. 18.2Mbits is probably the max you will get.
4. The article compares live broadcasts to VOD. Hey, let's just forget about the fact that VOD can be encoded with multi-pass. Same thing right? Jesus.
5. 50% H264 won't beat MPEG2 at 2x the bitrate? Must mean all MPEG2 encoders are built alike.
6. The math for DOCSIS user allocation to bitrate is completely wrong. Let's ignore edge device caching, multicast delivery to the edge, and statmuxing!
7. AppleTV's maximum bitrate is 5Mbits, but 99% of the time encoding at 4.85Mbits yields the optimum bitrate with the added jitter and packet overhead.
8. Microsoft's HD quality can in many cases surpass over the air (ATSC) MPEG2 1080i. Most stations are going exclusively 720p24, and running at 12-14Mbits MPEG2. Some as low as 9-10.
9. 6-8Mbits is actually a 'sweet spot' for 720p24H264 in many implementations.
And lastly HD is defined strictly by resolution, format, aspect ratio, pixel count, frame/field and associated rate. People need to stop pulling some bitrate out of their ass just to tout that as being 'HD'. It's not, and pertains to user *perceived quality*. It is irrelevant to the spec.
AppleTV *fails* because it has horrid gamma representation and low-quality image enhancement on the H264/MPEG4 decoding, which actually ends up over-sharpening edges and producing artifacts that ruin the image.