Of course this is pretty neat especially if your connected to a wifi hotspot but doing any sort of streaming over EDGE (at least from our tests) things are slow, buffering, hangs in the trailer etc. If you want to stream over EDGE your going to greatly reduce your quality event to the point where your seeing just a macro block slide show with lots of latency/buffering.

I put together a iPhone demo page to test out a video I encoded here. I recommend loading this on wifi connection, but would be curious to see how it runs on EDGE for some people.

I have encoded and tested the following:

mpeg4 + aac (hinted non hinted)

• doesn’t work via DSS or direct html link Safari doesn’t understand RTSP and http:// linked videos it wants to load into memory.

h264 + aac (hinted non hinted)

• doesn’t work via DSS or direct html link Safari doesn’t understand RTSP and http:// linked videos it wants to load into memory.

Asking my buddy to visit m.youtube.com via safari and test a video from the page also doesn’t work for him either.

Error: safari can’t open the page because the address is invalid

So, unless you can develop your own custom application like the youtube one right now looks like we are out of luck.

User Agent String for iPhone is:

Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3

If anyone comes up with a solution I would love to hear it.

With all of that said anyone who has an iPhone would you please visit the best video sites and test out a few videos at http://mvstreamer.mobi .

I’m also looking for any videos encoded for the iPhone so I can add in streaming support for iPhone users. I don’t expect this to look nice since the video specs are 320×240 or 640×480 at EDGE data rates which isn’t great and not to mention the latency issue. I will be adding bigger video sizes soon but don’t expect any miracles for those screen sizes, getting a good looking qcif video at the current data rates on EDGE is tough enough with out turning it into a blocky slide show.

iPhone Specs from Apple:

Video formats supported: H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second, Low-Complexity version of the H.264 Baseline Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; H.264 video, up to 768 Kbps, 320 by 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats

UPDATE: My buddy is in line for his iPhone so Ill be able to do some tests soon, but I would still like to hear from other iPhone users.

My original compile options for ffmpeg : --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib --disable-debug --enable-mp3lame --enable-libogg --enable-vorbis --enable-faad --enable-faadbin --enable-faac --enable-pthreads --enable-xvid --enable-x264 --enable-a52 --enable-a52bin --enable-amr_nb --enable-amr_nb-fixed --enable-amr_wb --enable-memalign-hack --enable-shared --enable-gpl

Things that have changed are the addition of adding “lib” do most everything.. So –enable-xvid will be –enable-libxvid. Most of these can be found by typing ./configuration –help

So this is just a fyi if you haven’t compiled ffmpeg in a while to prob add “lib” to most everything

The next changes have to do when encoding video and most of them deal with changes in the audio switches.

changes:

old: -acodec amr_nb
new: -acodec libamr_nb

old: -ab 12
new: -ab 12.2k or various other options but all require “k” behind them.

old: -acodec aac
new: -acodec libfaac

hopefully this helps out and your not pulling your hair out or Googling around to find the changes cause well apprently their is no good change log with this type of information.

First you figure out what resolution your current video is as. So im going to use the super man trailer I have been testing with as an example which is at 1280×544, which is in some sort of wide screen video format.

Step one is to divide the width of the source with the width of qcif.

1280/176 = 7.27 ...

Next divide the result from step one by the height of the original video which is 544.

btw I rounded up to 7.3

544/7.3 = 74.5...

So giving these 2 calculations we now have the new height of the video based upon a qcif resolution.

176 x 75 (I rounded up)

Here is where the issue lies if you encode your video with ffmpeg at that resolution your breaking qcif compliance which most phones require so your going to immediately break playback on most phones.

So what you do is use the padtop and padbottom options in ffmpeg to add black bars to your video but be carefull as you will see in our example they needs to be multiples of 2.

(144-75)/2 = 34.5

So since 34.5 isn’t valid pad value for ffmpeg you have to fudge your numbers a bit.

(144-76)/2 = 34

Which now gives you a valid number thats divisible by two.

So your end result when encoding this video would be

ffmpeg -i yourvideo.avi -f 3gp -vcodec h263p -r 7.4925 -s 176x76 -padtop 34 -padbottom 34 -acodec amr_nb -ac 1 -ar 8000 -ab 12 -b 32k output.3gp

you will notice a few things right off the bat, you cannot use -vcodec h263 since it wont let u encode anything non qcif resolution -vcodec mpeg4 doesn’t have this limitation but you need to encode for h263 this is what you use. Pad top and bottom add the black bars to the video how ever your not done because this video will not -hint with MP4Box and it will actually remove the video stream if you try it.

MP4Box -hint -3gp output.3gp
Converting to 3GP file...
[3GPP convert] Video format not supported by 3GP - removing track ID 1
[3GPP convert] Setting major brand to 3GPP V5 file
Hinting file with Path-MTU 1450 Bytes
Hinting track ID 2 - Type "samr:samr" (AMR) - BW 13 kbps
Saving output.3gp: 0.500 secs Interleaving

What you need to do then is re-encode that video that was just created again with the proper qcif format. I know this sucks and re-encoding a video again looses some quality but currently this is the only solution I found for h263, so far my tests for mpeg4 and h264 don’t require this additional re-encoding.

You can see the result if your point your phone over to http://mvstreaming.mobi

So given this formula will help you keep the proper aspects of wide screen videos, it may look a lot smaller on the mobile phone screen and you may not care and just encode it all to 176×144 wide screen or not.

On another note, if anyone builds a php, or perl script that can do this calculation I would be interested in looking at it.

The issue is taking content that is shot in HD and converting it to the mobile phone screen but keeping the proper aspect of the HD content. This leads to a few issues, first of all QCIF (Quarter Common Intermediate format – 176×144) which is at 4:3 aspect ratio.

A test clip im using is at the resolution of 1280×544, its not quite 720p resolution which is 1280×720 but thats besides the point, taking that resolution and fitting it into QCIF causes the aspect of the HD clip to fit to the 4:3 ratio.

The problem is encoding it at a lower res than 176×144 can cause issues with some mobile phones, ie QCIF is a very strict standard resolution that mobile phones have stuck to and some players blow up if its not at the proper res.

What im trying to figure out is how to convert down the clip and use -padtop , -padbottom and -padcolor ffmpeg settings which are supposed to create crop bars for you in black. I have yet to get a result that I like so far. So Im wondering if anyone has a suggestion to do this with either ffmpeg or mencoder.