mp4 Streaming Restarts on Player Seek

2G wrote on 1/28/2010, 11:59 AM
I have a problem that I can't figure out. I render mp4 using the MainConcept AVC/AAC renderer for streaming from my streaming server and also for playing on iPods/iPhones. With any file I render now, if I try to seek to some spot in the middle of the clip on the Flash player or if I use the slider bar on my iPod to try to seek, the video always starts over. It will not seek. I have tried several templates on that renderer. Same result.

Now here's the weird part... I went back to videos I rendered a few months ago, and they all seek just fine. Something has changed. I can't pinpoint precisely when it changed. But it's been sometime in the past few months. Videos I rendered on Sept 12 work fine. I've moved from XP to Win7 in that timeframe. But I wouldn't think that would affect this. I believe I also moved to 9.0c during that timeframe.

Have I screwed up something in the render template? Has anyone else encountered this problem?

If you are rendering for a streaming server, what renderer/template/settings do you recommend?


dlion wrote on 1/29/2010, 8:56 AM
1 - try using mp4faststart on your mp4 files.
2 - try using the sony avc preset instead of the mainconcept.
3 - use handbrake on your mp4 files, basically keep all the settings the same.
2G wrote on 1/29/2010, 8:56 PM
Actually, yesterday I tried the sony avc renderer instead of mainconcept, and it now works. But that still begs the question, what changed with mainconcept since september, and what is wrong with the mp4 file structure that makes it not seek? I was rendering with mainconcept in september for the mp4s that are still playing fine.

I'm not familiar with mp4faststart. Is that a tool that rearranges the moov atom for progressive play like QTIndexSwapper?

I don't understand what you mean about handbrake and keeping all settings the same. What's handbrake? And keep them all the same as what? The settings I'm using now are obviously wrong. What's the significance of keeping them all the same?

BudWzr wrote on 1/29/2010, 9:22 PM
Why do you suspect the MC encoder? Maybe MC didn't "play ball" with Apple or offended Herr Jobs in some way, and they got punished via itunes update.
2G wrote on 1/30/2010, 9:33 AM
Why do I suspect the MC encoder? Simple... I use the MC encoder and the mp4 video won't seek. I use the Sony encoder and the mp4 seeks.

It's not just on the iPod that it won't seek. I have a streaming server ( that serves video to Flash players.

1) FLV video streams and seeks
2) Sony AVC encoded mp4 streams and seeks
3) MC AVC encoded mp4 (September era encodes) steams and seeks
4) MC AVC encoded mp4 (current encodes) stream but DON'T seek

Sure looks to me like it's related to the MC encoder (or my settings for the MC encoder).

Is anyone else rendering for streaming and/or iPod/iPhone and getting different results than those above? What settings are you using on the MC renderer if it's working for you?
CClub wrote on 1/30/2010, 10:14 AM
I'm getting the "non-seeking" MainConcept mp4 problem also. I had posted this[/link] without any responses.
dlion wrote on 1/30/2010, 12:23 PM
mp4faststart. Is a tool that rearranges the moov atom for progressive play like QTIndexSwapper. it may be all you need or may not work on a particular file.

then, escalate to handbrake (recommended by the folks at longtail, maker of the JW player).

handbrake is a freeware video transcoder. Keep the file attributes of the file you open w/handbrake- you may need to tweak settings to make sure handbrake doesn't change anything (frame rate, size...), just inserts the markers players need to shuffle. apparently, the MC encoder does not add this metadata to its encodes.
goodtimej wrote on 1/30/2010, 11:44 PM
Great info on this thread. Thanks
2G wrote on 1/31/2010, 7:49 PM
Well, the fact that others are getting the same seeking problem with MC at least lets me know that it's not just my installation. I'll continue to investigate.

Thanks for the info on MP4FastStart. I have been using QTIndexSwapper to fix mp4 moov atom for progressive download play for several months. But I've been very frustrated that QTIndexSwapper fails on video over about 45 minutes long. I tried MP4FastStart, and it works on the longer files. (Doesn't change the seek problem, but does fix the moov atom problem)

I'll take a look at handbrake. There is still something wrong, in my opinion, with the MC renderer if I have to use a 3rd-party post-processor to make it "work right", though...

Thanks again.