trouble splitting and joining with mp4box

[charlieship]

here is my file about 10MB strttest.mp4
http://www.sendspace.com/file/81m2mm


I'm attempting to extract then join back, the first 10 seconds of it. But words disappear from the combined file


mp4box -split-chunk 0:5 strttest.mp4
mp4box -split-chunk 5:10 strttest.mp4
mp4box -cat strttest_0_5.mp4 -cat strttest_5_10.mp4 strttestb.mp4

The first 10 seconds of strttest.mp4 has the words "model of the universe" but strttestb.mp4 does not, it loses those words for some reason.

Here is what mediainfo says about the file strttest.mp4, if it helps.

C:\>mediainfo strttest.mp4
General
Complete name : strttest.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 10.2 MiB
Duration : 2mn 0s
Overall bit rate : 713 Kbps
Movie name : strttest.mp4
Writing application : Lavf52.108.0

Video
ID : 1
Format : MPEG-4 Visual
Format profile : Advanced Simple@L5
Format settings, BVOP : Yes
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default (H.263)
Codec ID : 20
Duration : 2mn 0s
Bit rate mode : Variable
Bit rate : 581 Kbps
Maximum bit rate : 9 500 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.112
Stream size : 8.31 MiB (81%)
Writing library : XviD 63

Audio
ID : 2
Format : MPEG Audio
Format version : Version 2
Format profile : Layer 3
Codec ID : 69
Duration : 2mn 0s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Sampling rate : 22.05 KHz
Compression mode : Lossy
Stream size : 1.83 MiB (18%)
Writing library : LAME3.98.4

[Baldrick]

You could try avidemux. Under video and audio choose copy. BUt you can't cut exactly, only at the keyframes without reconverting.

[charlieship]

i'd like to get it done with mp4box

[Selur]

don't think any tool can do what you want without reencoding due to the positioning of the key frames in the stream,..

[charlieship]

it looks like mp4box can do encoding and i'd like to use it but I can't see what the correct options are to use.

[Selur]

Mp4box can't do any reencoding, so you won't find a switch for encoding,...

[charlieship]

so what use is mp4box's splitting option if it loses bits?
and if mp4box can't split them properly, and can't re-encode, what's it used for?


can you name me a bunch of command line tools like 4/5 that'd do it? I know avidemux, but others..

and a bunch of GUI tools like 4/5 that'd do it?

ta

[Selur]

It should not lose bits,... it's main purpose for me is extracting, muxing and tagging of mp4 files.
Don't know of any command line tool that supports smart-reencoding during splitting.
Personally i would remux to avi, use Virtual Dub, which has smartrendering support, to cut and join and if needed later remux to mp4 using mp4box.

Cu Selur