How do I edit the video length of an MP4? - hex

How do I change the video length of an MP4 through a hex editor?
I'm pretty sure its somewhere under the mvhd section of the hex content, but I'm not sure where.

Found the video you were talking about (or alternative)
https://www.youtube.com/watch?v=UxHQ7dW6M2s

Related

Shrinking MP4 for Wordpress

I am trying to compress a video for wordpress, as each time I open up my webpage the video barely loads and then freezes. How should I go about compressing the video (I have already zipped it and used a program, but at 324kb it still seems too large). I have heard something about changing the bitrate, is this helpful/how can I do that? I would like to keep it in an mp4 if possible.
The only way to change the bit-rate of a video file is to re-encode it. There are plenty of software that are capable of doing so, my favorite being avidemux which is free and reliable.
Open your file in the app, choose an encoding & a bit-rate, hit "save video" and you're good to go.
You might have to try a few different bit-rates until you get a file that will both load fast and look good on you website.
Be sure to always use the highest-quality source file available for the re-encoding operation, since re-encoding your video will always result in a decrease of your video's quality.

Image represented by text - what is it called?

I've seen in some sample code and other places what appears to be just a bunch of random text, but is rendered as an image.
For example:
background-image: url(data:image/png;base64,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);
...which creates a checkbox.
What I'm wondering is, what is it called when you represent an image as text like this? I ask because I want to look for image editors that will do this for me (or see if my current editor has this type of export) and I don't know what to search for.
It's encrypted in BASE64, you can do it HERE
It's all in the code ;)
This is a Base64 encoded data-URI.
Try it here: http://www.base64-image.de/

Why just sound is played for some mp4 files?

I have some mp4 files that just sound is played not video with jw player and f4 player. But all other mp4 files are playing correctly.
what can be wrong?
Pump the video through Handbrake with the default options, plus check "Web optimized." I'll wager that it plays just fine in JW Player after that.
It's a freebie: http://handbrake.fr/
MP4, like any other format, requires specific CODECs for playback. No matter what player you are using, if you do not have the required CODEC for THAT specific clip, you will not play it back correctly. To make matters worse, audio and video are seperate CODECs.
This is why you may hear audio, but see no video. It's also why some clips play, and others don't. Different CODECs.
A CODEC is a "COder/DECocer" for audio and video streams. Unless you can view the properties of a particular clip, you really don't know what CODEC the author used.
Make sure to encode your videos in H264.

How to View source page using Wireshark?

Is there a possibility that a website's source page can be captured and viewed using Wireshark ? I do not need the header packets, what I am looking for is the full source page of any site that I open while running the Wireshark.
Yes - in the list of packets, right-click and say "Follow TCP Stream". For uncompressed content, that's it.
If the content is gzipped, you need to save that output to a file, use a decent text editor (that won't break binary content) to strip away the headers, then run gunzip to decompress it.
(If anyone knows of a way to make Wireshark do all that itself, I'm all ears!)
Edit: Just noticed the 'chunked-encoding' tag... that makes it harder. Editing away the chunk headers in the text editor should be possible, but tedious if there are a lot of them.

Get frame width/height of an mp4 file

Is it possible to get the frame width & height of an .mp4 file using ASP.NET?
I know how I can get the width & height of an image (by using a Bitmap object), but I'm not sure whether this is possible with video formats.
I'm using JWPlayer to display uploaded videos through the web application, and I want to set the width/height as a proportion of the actual video width/height.
As I like to do things the hard way I would go for reading the file meta data to try and find the information I needed.
I think this has some info about the structure of MP4 files but not had chance to read through it: http://xhelmboyx.tripod.com/formats/mp4-layout.txt
If you are happy to use a 3rd party library then this one seems to provide the data you need and looks to work with many other file formats too: http://mediainfo.sourceforge.net/en
Hope that get you somewhere ;)

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