IPB

Welcome Guest ( Log In | Register )

CBR or VBR - how to detect?
dand
post Dec 7 2011, 17:37
Post #1





Group: Members
Posts: 216
Joined: 9-December 02
From: Croatia
Member No.: 4037



Hi,
I have an AAC file that is being reported by the "MediaInfo" tool as VBR. How do these tools judge if AAC is CBR or VBR? How is AAC CBR different than AAC VBR, is there a limit in frame size differences accros file?

Thanks...
Go to the top of the page
+Quote Post
 
Start new topic
Replies
dand
post Feb 3 2012, 10:56
Post #2





Group: Members
Posts: 216
Joined: 9-December 02
From: Croatia
Member No.: 4037



QUOTE (dand @ Dec 7 2011, 17:37) *
Hi,
I have an AAC file that is being reported by the "MediaInfo" tool as VBR. How do these tools judge if AAC is CBR or VBR? How is AAC CBR different than AAC VBR, is there a limit in frame size differences accros file?

Thanks...



Ok, here is a code snippet where MediaInfo decides on the bitrate:

CODE
void File...()
{
        if (FrameSize_Max>FrameSize_Min*1.02)
        {
            Fill(Stream_Audio, 0, Audio_BitRate_Mode, "VBR");
            Fill(Stream_Audio, 0, Audio_BitRate_Minimum, ((float64)FrameSize_Min)/1024*48000*8, 0);
            Fill(Stream_Audio, 0, Audio_BitRate_Maximum, ((float64)FrameSize_Max)/1024*48000*8, 0);
        }
        else if (Config_ParseSpeed>=1.0)
        {
            Fill(Stream_Audio, 0, Audio_BitRate_Mode, "CBR");
        }
}



Seems like they flag stream as VBR if max frame is more than 2% greater than the min frame.
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 22nd September 2014 - 06:31