iPhone AAC-LC

[Speedy523]

Hey everyone, im trying to encode all my movies for phone as im going on vacation for a few months soon, but ive been running into a problem. I re-encoded the video stream to h.264 and it plays back perfectly on the phone, but after converting the audio stream to AAC-LC, and muxing it together, it seems the phone wont play the audio, but will playback the video. And after attempting to watch the film, the phone completely stops the playback of audio until a restart.

After some searching i found out that apple says the maximum bitrate that the iPhone can playback with h.264 video is 160 kbps AAC-LC, which seemed to be the problem, since i encoded the audio stream at ~650 kbps AAC-LC. But even after re-encoding the audio stream to 160 kbps and 150 kbps, the phone won't play it back. I even had MeGui (which im using to encode and mux) use all the iPhone profiles and even tried setting the extension in MeGui for the audio to m4a, and still no luck.

Also, the video plays back fine in ZoomPlayer, VLC, QuickTime, and iTunes, it just doesnt play back the audio on the phone. I've also tried the videos on both the iPhone 3GS and the iPhone 3G to rule out the problem with that particular phone, but it still wont play on either. I've also tried re-encoding the audio to mp3, but after listening to it, it pales in comparison to aac-lc, which is why i won't give up on it :)

So if anyone knows how i can get the audio to playback without losing much quality, it'd be appreciated :D

Thanx in Advance!

[nurbs]

Is your track 5.1? Maybe the iphone only supports stereo.

[Speedy523]

Is your track 5.1? Maybe the iphone only supports stereo.

yes it is, and after i posted this, i tried using the iPod - High quality preset, which had the settings of Downmix to stereo and convert to adaptive bitrate of 192 (i used constant before), but MeGui just hangs on PreProcessing for over 45 minutes. Like the process is still working, and using cpu power, but its not moving on to the actual encoding like before.

Right now im trying it in foobar, if that doesnt work, ill use my old setting with MeGui but just check the downmix and see if it works

EDIT: It worked! the problem was the channels. Now i guess its time to change it to VBR and see how high i can raise the bitrate before the phone freaks out :)

Despite what Apple says on their website about the iPhone only handling up to 160 kbps AAC-LC, I just re-muxed the mp4 with a max quality vbr playing at approx. 326 kbps and it played back flawlessly. Now its time to see how high i can raise the avc level for the video while still getting perfect playback :)

[tebasuna51]

For stereo audio AAC you don't need more than 160Kb/s, if you use more you can't listen the difference even with very good audio equipment.