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Slow seek after packaging h264 with mp4box

Authoring
Bill
2012-07-06
2013-06-05
  • Bill

    Bill - 2012-07-06

    I have an h.264 file created with the TI DM365 chip. When I play it in VLC, it seeks to the end of the file very quickly. However, when I package it into an mp4, even without audio, the seek to the end of a 40 minute file takes around 4 minutes.  I tried using the :forcesync option, but I suspect that was intended for other cases.

     
  • Romain Bouqueau

    Romain Bouqueau - 2012-07-06

    Hi,

    I have the feeling your h264 is encoded with open GOPs, am I right? Could you try to use the ":forcesync" flag and tell if it's better?

    Romain

     
  • Bill

    Bill - 2012-07-06

    @rbouqueau - Yes, I tried using :forcesync, but didn't see a difference in the seek time.  Here's my command line:

    c:\development\idvrconvert\idvrconvert\bin\Release>mp4box.exe -import "C:\development\vnl01122012-155043.h264":forcesync "C:\development\vnl01122012-155043.mp4"

     
  • Romain Bouqueau

    Romain Bouqueau - 2012-07-06

    Is there a possibility for you to share a sample? (Send a PM if you can't share it publicly).

    Romain

     
  • Bill

    Bill - 2012-07-06

    I have a small (approx 1.3MB sample) I can email you.  My email is wlmyers at aol.com.  I'll send the h264 in reply.  Or I can post somewhere else for your convenience.  Thanks.
    Bill

     
  • Romain Bouqueau

    Romain Bouqueau - 2012-07-07

    Hi Bill,

    We've received the files and understood the problem. We'll let you know when we patch it. Please note you will need the latest VLC (2.0.2) to read it correctly once fixed.

    Just for our information, is this a h264 raw from a camera? Did you encode it using a tool?

    Romain

     
  • Jean Le Feuvre

    Jean Le Feuvre - 2012-07-13

    Now fixed on SVN, thanks for the sample

     
  • Bill

    Bill - 2012-07-13

    That's awesome.  When will there be a windows build with this patch included?

     
  • Bill

    Bill - 2012-07-16

    Romain,
    This seems like a definite improvement, but the seek still seems to take about 1.25 minutes to seek toward the end of our 40 minute file (it used to take almost 4 minutes).  Here's some more information: I can generate an mp4 with ffmpeg that seeks very quickly, but takes 10 minutes to create.  Is there some option that I need to set with mp4box to make the seek faster?  What settings did you use on the h264 file that I posted?
    Thanks.

     
  • Romain Bouqueau

    Romain Bouqueau - 2012-07-16

    Bill,

    Which player do you use? The GPAC player (osmo4) and VLC 2.0.2 both seek instantaneously.

    My CL: mp4box -add vnl01122012-155043.h264:forcesync -new tmp.mp4

    Romain

     
  • Bill

    Bill - 2012-07-20

    Got it.  Forgot the :forcesync.  Works beautifully.  Thanks, guys!

     
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