philipl | # 1 | 2009-12-02, 04:02 | Report

Hi all,

Just got my new n900 and I'm suitable pleased but I'd like to understand what it's H.264 capabilities are.

I did some quick experiments with handbrake 0.94 and I found that the 'Main' preset (Main@3.0) failed while the iphone preset (Baseline@3.0) succeeded.

I wonder if anyone knows what the exact limits are, with respect to bitrate, dpb size (implying ref frames) and whether any particular Main features are supported (CABAC definitely isn't!)

Thanks!

--phil

(I used an anime DVD source and I was pleased that the 720x480 and variable frame rate didn't cause problems.)

zaheerm | # 2 | 2009-12-02, 09:39 | Report

baseline is supported only, not sure what the bitrate and resolution limits are (although |I think 800x480 H264 baseline will work but 720p will not)

Psymastr | # 3 | 2009-12-03, 00:25 | Report

I was going to fiddle with the handbrake presets after I get my unit tomorrow and make a preset, unless someone already has.

Imtiyaz | # 4 | 2009-12-03, 00:36 | Report

I am also interested settings for handbrake i just my n900 and want to rip some dvds

REMFwhoopitydo | # 5 | 2009-12-03, 11:49 | Report

how does this translate to Adobe CS3 encoding?

.flv/On2 isn't giving me the quality i need at a less than 20Mb file-size at 800x480.

using h264/MP4 with a 800x480 res and a 1MB target with a 1.6MB maximum i get a 16MB file size. This is still a little crappy.

obviously i can boost the bit-rate sky high, but at what point will a mobile device of n900 calibre cease to be able to play it?

and at what point are you using a bit-rate that exceeds typical 3G bandwidth for streaming video?

cheers

floffe | # 6 | 2009-12-03, 12:04 | Report

Not sure about the rest but this isn't too hard to answer: Most HSDPA gives a theoretical max of 7.2Mbit/s, that is 900kB/s. Don't count on actually getting out more than half of that reliably, though (in Sweden they're only allowed to advertise that as "up to 6Mbit/s" due to the overhead etc). Regular 3G is 384 kbit/s max.

REMFwhoopitydo | # 7 | 2009-12-03, 12:24 | Report

thanks, but you're confusing me as you are mixing KB/s and kbits/sec.

If I have a 20,000KB video file (20MB), that runs for 140 seconds, then i get an actual bandwidth of 142KB/s......... i think.

if 3G (a useful baseline) is really only 384kbit/s then that gives me about 40KB/s, i.e. not enough to stream my video.

however if 3G is really 384KB/s then even if it works at only 50% efficiency I still have enough bandwidth to stream my 20MB video file to my phone.

which is it?

floffe | # 8 | 2009-12-03, 12:32 | Report

3G is 384 kbit/s, so you won't be streaming any quality stuff there.

Alex Atkin UK | # 9 | 2009-12-03, 12:34 | Report

In the UK, on O2 or T-Mobile I get around 1.5Mbit. Thing is though, its likely to fluctuate lower than that too so for streaming, its questionable what you could get away with.

I find it puzzling you do not get good quality out of that bitrate though. But that said, unless you are transcoding from HD then there is not much point trying too hard. Transcoding from DVD will never be ideal as 800x480 is a higher resolution than NTSC DVD.

REMFwhoopitydo | # 10 | 2009-12-03, 13:34 | Report

the source is a 3D animation that is:
2:19sec
333MB
1536x1152
h.264/.mov

and we are a graphics company, and thus pretty picky about the image quality, given it is our stock in trade.