Supported H.264 features on N900?

[philipl]

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]

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.)

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]

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

[Imtiyaz]

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

[REMFwhoopitydo]

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)

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]

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

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]

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

[Alex Atkin UK]

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]

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.

[Rushmore]

Standard res avi and divx files look very good on the N900. MP4 (that actually work) look better (IMO) than the same files on the Droid.

Still, MP4 needs an update on the N900, since some MP4s that play fine on the Droid do not play on the N900.

added:

This is a nice thing about Maemo compared to Android. Maemo for the N900 can get codec updates. Android can not, since part of the framework and Android is not going to add a bunch of codecs that will work ok for some chipsets and not for others.

Up to the phone carrier and the manufacturer to request a driver add-in. That does not happen with Android (accept maybe the Sony versions).

[ArnimS]

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.

Then we await your expert advice on best handbrake encoding options.

EDIT: Here's what i'm using to rip old TV series (progressive PAL). 680x480 4.25/3 anamorph, ffmpeg, monophonic, noisefilter.

<key>PresetBuildNumber</key>
<integer>2009112599</integer>
<key>PresetDescription</key>
<string>Optimized to scale older progressive-scan DVD sources (video noise, monophonic) to N900 mp4 optimized format, stretched to 4.25/3 aspect ratio.</string>
<key>PresetName</key>
<string>N900-DVD4.25/3</string>
<key>SubtitleList</key>
<array>
</array>
<key>Type</key>
<integer>1</integer>
<key>UsesPictureFilters</key>
<integer>1</integer>
<key>UsesPictureSettings</key>
<integer>1</integer>
<key>VideoAvgBitrate</key>
<integer>1400</integer>
<key>VideoEncoder</key>
<string>MPEG-4 (FFmpeg)</string>
<key>VideoFramerate</key>
<string>Same as source</string>
<key>VideoGrayScale</key>
<false />
<key>VideoQualitySlider</key>
<real>20</real>
<key>VideoQualityType</key>
<integer>1</integer>
<key>VideoTargetSize</key>
<integer>680</integer>
<key>VideoTurboTwoPass</key>
<true />
<key>VideoTwoPass</key>
<true />
<key>anamorphic</key>
<true />
<key>par_height</key>
<integer>480</integer>
<key>par_width</key>
<integer>680</integer>
<key>x264Option</key>
<string>b-adapt=2:rc-lookahead=50</string>


i extracted that from ~/.config/ghb/presets

EDIT2: N900 demo video looks pretty nice - here's what mplayer reports for it:

VIDEO: [MP4V] 800x480 24bpp 25.000 fps 3543.6 kbps (432.6 kbyte/s)
[V] filefmt:44 fourcc:0x5634504D size:800x480 fps:25.000 ftime:=0.0400

[Jack6428]

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?

cheers

I have avi files on the N900, with 4000 Kbps bitrate and they play well...i think that is the maximum the N900 can handle bitrate-wise. Resolution-wise it is 800x480, atleast defaultly for now, until perhaps VLC and final decoders are released enabling 720p playback. But i'm not sure how that will perform.

Cheers