MPEG2 and HD-DVD quality ... ???

[Sagittaire]

HD DVD was launched early. Yesterday, the first HD DVD players were being sold in Japan and a reader managed to grab one and two discs, and he was not pleased. I haven't managed to get any details yet as to which codec was used and if the disc was single layer or double layer, but 1080i content encoded with MPEG-2 to a single layer HD DVD would indeed be a disaster.. two times the space for 4 times the amount of pixels - you do the math.

1) Objective pixel quality


|---------------|--------------------|--------------------|--------------------|
| | files sizes | bit/(pel*fps) | bit/(pel^0.75*fps) |
|---------------|--------------------|--------------------|--------------------|
| q2 1024*576 | 3389 Kbps | 0.239 bpf | 6.63 sci |
| q2 720*400 | 1890 Kbps | 0.273 bpf | 6.33 sci |
| q2 512*288 | 1143 Kbps | 0.323 bpf | 6.32 sci |
| q2 384*208 | 714 Kbps | 0.372 bpf | 6.26 sci |
|---------------|--------------------|--------------------|--------------------|
| q3 1024*576 | 2067 Kbps | 0.146 bpf | 4.04 sci |
| q3 720*400 | 1188 Kbps | 0.172 bpf | 3.98 sci |
| q3 512*288 | 735 Kbps | 0.207 bpf | 4.07 sci |
| q3 384*208 | 462 Kbps | 0.241 bpf | 4.05 sci |
|---------------|--------------------|--------------------|--------------------|
| q4 1024*576 | 1492 Kbps | 0.105 bpf | 2.92 sci |
| q4 720*400 | 875 Kbps | 0.127 bpf | 2.93 sci |
| q4 512*288 | 548 Kbps | 0.155 bpf | 3.03 sci |
| q4 384*208 | 344 Kbps | 0.179 bpf | 3.02 sci |
|---------------|--------------------|--------------------|--------------------|
source 1280*720
resize with lanczos
encoding with XviD



|----------------|--------------------|--------------------|--------------------|
| | files sizes | bit/(pel*fps) | bit/(pel^0.75*fps) |
|----------------|--------------------|--------------------|--------------------|
| q20 1280*720 | 4026 Kbps | 0.182 bpf | 5.63 sci |
| q20 720*400 | 1728 Kbps | 0.250 bpf | 5.79 sci |
| q20 512*288 | 1057 Kbps | 0.299 bpf | 5.85 sci |
| q20 384*208 | 661 Kbps | 0.345 bpf | 5.80 sci |
|----------------|--------------------|--------------------|--------------------|
| q25 1280*720 | 2074 Kbps | 0.094 bpf | 2.90 sci |
| q25 720*400 | 924 Kbps | 0.134 bpf | 3.09 sci |
| q25 512*288 | 573 Kbps | 0.162 bpf | 3.17 sci |
| q25 384*208 | 363 Kbps | 0.189 bpf | 3.18 sci |
|----------------|--------------------|--------------------|--------------------|
| q30 1280*720 | 1023 Kbps | 0.046 bpf | 1.43 sci |
| q30 720*400 | 460 Kbps | 0.067 bpf | 1.54 sci |
| q30 512*288 | 286 Kbps | 0.081 bpf | 1.58 sci |
| q30 384*208 | 181 Kbps | 0.094 bpf | 1.59 sci |
|----------------|--------------------|--------------------|--------------------|
source 1920*1088
resize with lanczos
encoding with x264


for same quant level (aka same mathematical quality by pixel) you must use something like bit/(pel^0.75*fps) for MPEG codec

I use for reference PAL DVD source at 5 Mbps
720*576 = 414 000 pixel
5 000 000 / ((720*576)^0.75*25) = 12.24

If I want same pixel quality at 720p for same source I must use 9.5 Mbps
If I want same pixel quality at 1080p for same source I must use 17 Mbps

2) Subjective pixel quality

8*8 DCT block has not same relative size for 576p, 720p or 1080p:

720*576 / 8*8 = 6 480 block
1280*720 / 8*8 = 14 400 block
1920*1088 / 8*8 = 32 640 block

If it's easy to see block for 576p, it's more difficult to see the same block at 720p and really more difficult to see the same block at 1080p. Same observation for ringing: with 8*8 DCT ringing artefact size are always the same but not relative size.

3) Conclusion

You can make more than 120 min 1080p MPEG2 encoding at 15 Mbps with very high quality for HD-DVD single layer.

IMO 15 Mbps MPEG2 1080p encoding done better visual quality than Quick Time 7 AVC trailer.

[Golgot13]

I don't see that HD DVD support 1080p in MPEG2 (sure not in 25p or 29.97p) ??


First player support only 1080p => 1920x1080, 1440x1080 or 1280x1080 at 24p in VC1 or H264

May be a update (not sure because first version of HDMI chipsets don't support it)
will upgrade HD DVD player to support 1080p at 25p, 29.97p or 60p in VC1 or H264.


Golgot13
Membership of "HD DVD"

[siddharthagandhi]

HDDVD will suport MPEG-4 AVC, VC-1, and MPEG-2

its japan where they released the MPEG-2 first not in America...i think i read somewhere the first in America will be VC-1