Problem converting combined motion jpeg and mp4 audio file into other forma

[Selur]

that definitely does not happen here,.. so would be nice if another user could check this.

Cu Selur

[Anonymous3]

I tried

mp4box -cat "video1.mp4" combined.mp4

where combined.mp4 didn't exist before hand, and it created a file that was the original doubled.

[Selur]

-cat is not an option that is ment to used on a single file
you might want to check out: http://gpac.wp.institut-telecom.fr/mp4box/mp4box-documentation/

[Anonymous3]

Yes I know that I was just doing an experiment.
The original thing I tried was -cat file1 -cat file2 outputfile

[Anonymous3]

problem only happens for the 1st file, the rest are fine.

i.e -cat file1 -cat file2 -cat file3 .... only file1 is repeated. Since it will be a time lapse I'm just going to ignore it as the end result is insignificant.

[Anonymous3]

I hope mp4box can handle working with the 10gb file I'm in the process of creating.

[Anonymous3]

Well that's nice... the mp4box -cat command also fixes the files so that these two steps

MP4Box.exe -add combine.mp4#video -raw 1 -new d:\test.jpg

and mux the raw stream with:

MP4Box.exe -add test.jpg#video:fps=20 -raw 1 -new d:\speedUpRemux.mp4

are no longer required. And also fixes the need to open up with a hex editor and change a value. hooray for -cat!

[Selur]

The only point of these steps was to:
1. increase the fps for playback
2. identify the stream properly, the sample you uploaded had the video stream marked as mp4v which was wrong since the stream is mjpeg coded, but it was mp4 compliant. The hex editor step was to change the mp4v tag to mjpeg so mplayer an other tools will have it easier to playback the stream. (current mplayer versions should not need it since mplayer was fixed to support these sort of files )

-> happy to hear you got it working and without the need to reencode the whole process is speedwise mainly only limited by the hdd speed.

Cu Selur

[Anonymous3]

If I have an avs script with the following:

ffvideosource("test.mp4").Selectevery(100)

I run it with WinFF and it plays just fine. How do I get it to output to an actual file?

Or is it meant to modify the original file?

[Selur]

avisynth will !always! output uncompressed video,...
so don't use it unless you want to reencode

[Anonymous3]

I need it to use the "Selectevery()" function.

[Selur]

Then you need to reencode the content.
Personally I would just change the fps by extractind the raw stream and remux it with a changed fps, but that's your decision.
(I did explain the raw extraction and remux procedure and it works fine here.)

Cu Selur

[Anonymous3]

The remux with a change fps produces the equivalent of selectevery() function? I swear I tried this and it didn't produce a speeded up video, maybe I was doing something wrong. I'll tried it again now actually.

[Selur]

The remux with a change fps produces the equivalent of selectevery() function?

No.
.Selectevery(100) -> drop frames (only takes each 100th frame)
changing the framerate will not change the content but the player will playback more frames per second

[Anonymous3]

Ok understood. The dropping frames is critical to what I want to do. So it looks like I do need to use Avisynth.

[Selur]

Or another ffmpeg/mencoder based tool that allows to drop frames.

[Anonymous3]

I don't suppose you know of one? I just did a search but couldn't come up with anything - though I'm probably just using the wrong search terms.

[Selur]

I personally use ffmpeg&mencoder via command line or via Hybrid but no clue about a 'simple' gui.

[Anonymous3]

I guess I'm going to have to go that route as I can't find another way. Hooray more command line tools to learn

So I can use ffmpeg to run the selectevery() function directly (i.e without having to go through avisynth)?

[Selur]

# select one frame every 100
select='not(mod(n\,100))'

see: http://ffmpeg.org/libavfilter.html#SEC48

-> yup, should work.