I am streaming h.264/mp4 videos to FlowPlayer. On some of the videos, when I seek to a new location by clicking on the player progress bar, the video simply restarts from the beginning. The strange thing is that it doesn’t happen on all videos. I went back to some videos from the fall, and it seeks correctly. But on all of the latest ones I uploaded, it just restarts.
I have the same JSP page for both. So I am certain the html/player code is the same. I’m pretty sure the videos were rendered the same. But I’m not 100% certain of that. (BTW… I don’t believe I’ve seen this problem with FLV files. But I really want to use mp4 instead of going to the extra step of creating FLVs)
I looked at the Wowza access log. The entries for the video that seeks correctly looks identical to the entries for the video that restarts.
Obviously, there is something that is causing the player/server to restart on all seek requests.
Any suggestions for where to start to correct this?
Thanks.
Jerry
What is the key frame interval on the video? It might be that the keyframe interval is super large. We can only seek to key frames. So if there are not a lot of keyframe it will jump to the closest one.
Charlie
Not really. I am not sure how to inspect the file to look for key frames or determine the key frame interval. The tool GSpot will give you some info but I don’t believe it will give key frame intervals. Hmmm. I am not sure.
Charlie
We really don’t have the tools to debug this. We just don’t inspect the file before we start playback. If you want to send me one of the files that is not working properly, I can take a look at it by hand. Send it to support@wowza.com.
Charlie
Hi. I also noticed this problem. I have a mp4 video with 10 sec key interval. Playing it with FLVPlayer.
myPlayer.seek(slideTime) always starts the video from the beginning.
hank
flvplayback.seek() seems to work fine with flv files but not mp4.
can’t tell if is wowza or the flash client or the communication between them
Thanks for the response.
I went back to my render settings, and can’t find a place to even control keyframes. There is a field called “number of reference frames” that is set to 2, but that doesn’t seem right that it would only have 2 keyframes no matter how long the video is.
I also used MediaInfo to look at the two mp4s, the one that works and the one that doesn’t. I can’t find anyplace in MediaInfo showing keyframe frequency.
What you say about keyframes makes sense. But I’m not sure how it could have changed. Is it possible to have keyframes so far apart that even an hour long video would restart if you click at, say, 59:00?
Would it have anything to do with constant vs. variable bit rates, or maximum/average bps?
Thanks.
Jerry
I have turned on debug level logging. I’m not familiar enough with the server to really know how to interpret everything in the logs. Is there something in there that would tell about keyframes, etc?
Jerry
But the frustrating thing is that it works on SOME mp4 files. If I could just figure out what the difference is between the two sets of files, I would be able to get around the problem.
Is there anything I can turn on in logs or tracing to see what is happening when a seek occurs (i.e. how Wowza decides what point it is going to seek to, etc.)?
Thanks.
Jerry