IPB

Welcome Guest ( Log In | Register )

Please provide an overview of the MP4 format and how to cut its audio, [TOS #6: was "mp4 file cutter" in CD Hardware/Software]
manimanik19
post Jan 12 2013, 14:05
Post #1





Group: Members
Posts: 9
Joined: 12-January 13
Member No.: 105823



I am working with mp4 file cutter.Could anyone please help me how to get the clear overview of mp4 format and how to cut them.
Go to the top of the page
+Quote Post
 
Start new topic
Replies
nu774
post Jan 13 2013, 04:50
Post #2





Group: Developer
Posts: 476
Joined: 22-November 10
From: Japan
Member No.: 85902



"MP4" is too generic. Maybe you are thinking of such that only contain one audio (probably AAC) track ?
At first you have to understand MP4 format by reading spec. You have to work mainly with some mp4 "box" structure such as stts, stsc, stsz, and stco as well as actual media samples (data) which goes under mdat box. All of these are considered as index to actual media samples, therefore required to edit.

AAC has inter frame dependency by overlapped nature of MDCT (and bit-reservoir). Therefore, it needs some pre-rolling to start playback at some arbitrary point.
When you implement cutting, you have to take this into account.
You will also need some way to express priming/padding samples for gapless playback.

This post has been edited by nu774: Jan 13 2013, 05:00
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: 18th April 2014 - 05:28