Develop Reference

How to convert video files to H.264 in C#

I've searched without any luck about how this can be done in C#. What i'm trying to archieve is a program that accepts video files and converts them to H.264. Here is an example of a page where you can do this interactively:
http://www.ofoct.com/video-converter/convert-to-h-264-video.html
Question:
How can I in .NET create a program that can do something similar to whats being done from that homepage I shared? Any help or input is highly appreciated, thanks!
EDIT:
The reason i want to do this is because it seems like videos play in both iOS and Android devices when this is done, perhapps there is another way to make sure videos can play in both iOS and Android?
EDIT again:
Lets say i film a Video on a phone Android/iOS, now I'm using a ASP.NET web api that I'd like to convert theese movies to H.264 before storing in Azure, Is this possible? If so, any pointers on how?

There is a wrapper available http://www.ffmpeg-csharp.com/
The main point is that no one is going to write an encoder due to how slow it would be in .NET

Encoding/decoding are provided by the OS, through Direct Show (in the past) or Microsoft Media Foundation. For example, the Microsoft Media Foundation already contains a [H.264 Video Encoder](H.264 Video Encoder).
The SDK is appropriate for C++ and Microsoft hasn't released a wrapper. There are wrapper projects available though, eg. MF.Net, DirectShow.NET, WindowsMedia.NET although it doesn't have any activity since 2012.
There are also similar questions in StackOverflow, that propose other options, like using Microsoft's Encoder, although H.264 support is available only in the Pro version

The only plausable way would be to call out to an encoding application such as ffmpeg.

I'm not sure that this what you need but you can download a nuget called
NR.VideoConverter :> then you can write this code to convert the type of video
like from mp4 to mvo or anything I'm not sure what is h264 but I did find it when I wanted to change my videos so it could help y
var converter = new NReco.VideoConverter.FFMpegConverter();
converter.ConvertMedia(FilePath, FilePath, NReco.VideoConverter.Format.h264);

Split and Merge MP4 video

I have a desktop application (mfc) in which now I have to implement split and merge of MP4 videos. I have searched a lot and found almost nothing online. Please help me with some hints on how to proceed and what to use. Splitting and merging should be done on timeline basis and not based on size. Code is in VC++
Can I achieve this with Windows Video Encoder? If yes, how to know about the exposed methods in WME?

DirectShow (now part of Windows SDK) provides editing services (EDS) but I would suggest ffmpeg (http://ffmpeg.zeranoe.com/builds/) as a better choice since it would support wider range of formats (e.g. H.264 - http://msdn.microsoft.com/en-us/library/windows/desktop/dd390353(v=vs.85).aspx).

WinRt C# Audio Library

I am looking to develop an app in C# WinRt, but was wondering what libraries are available for playback and for complicated manipulation. I am looking for a free library that allows for an extensive list of audio formats to be played (for example mp3, wma, wav, ogg, etc.) and also to be analyzed. Thats pretty much the basic functionality I would need. But if I could get picky, a library that can convert audio files between the formats would be handy. Doing a google search I came across the Naudio library, but it was not so greatly compatible with WinRt.Thanks for any tips or advice on this.

The current alpha build of NAudio 1.7 (available via NuGet) does contain a Windows RT assembly and the source code includes a simple demo of playback and recording as a Windows Store app. Since it uses Media Foundation, you'll be able to play most of the file types you suggested (although ogg won't be supported out of the box), and you can construct your audio pipeline to access the audio as floating point samples for analysis.
Things that aren't currently supported are using the Media Foundation encoders to encode, and the various reader/writer classes need to be re-written to use the WinRT asynchronous streams and File I/O APIs instead of the regular .NET ones. Hopefully these features will be added to the library soon.

Extracting and splitting a MP3 audio stream from an AVI file

I want to develop a desktop application by programming in C# and using the .Net framework 4.
The goal of my application is to extract a MP3 audio stream from a supplied AVI file.
I have learned from the Internet that an AVI file is a container and it might contain different audio streams.
If the supplied AVI file contains one MP3 audio stream at least then I want to extract it and split it.
I want to split the MP3 audio stream into MP3 audio parts identified with a start time and an end time.
I have looked on the Internet for any .Net library I could use but without success.
Does someone know what documented .Net library would be useful ?

Maybe you can try this:
Simple C# Wrapper for the AviFile Library
It is targeted at AVI video but there might be some clues as how to use the same methods to extract the audio only.
Either use it as-is or use the example to incorporate what you need into your own code.

Since tools for this task already exist, I see no point in creating another one unless you're curious about how to do this yourself and learn something new.
If so, using a ready-made library would defeat the entire idea of learning something which is why I strongly recommend you try implementing the splitter yourself.
You can find descriptions of the AVI file format online, that should get you started.

How to change the resolution of a WMV file in C#

I have a C# application and I would like to be able to read in a WMV file and then write out a WMV file with reduced resolution/quality.
Are there any built-in libraries for C# that can do this? Do I need the Windows Media Format SDK?
Does anyone have experience with this?
Can I use something like FFmpeg for this?

You will have to decode and re-encode ( = transcode) the file to do this. By doing so you will inherently reduce quality since you are working off an already compressed base.
One way to do it if you need a high degree of control is is with a DirectShow wrapper for C#, i.e. DirectShow.NET. then you just need to define a simple transcoding graph.
Actually the simplest way to do this is with Expression Encoder (the successor to Windows Media Encoder) which has a simple managed API and should do the job with much less effort than integrating DirectShow.
There's a summary article here. A simple transcoding job looks like this (sample from article, only presets changed):
MediaItem src = new MediaItem
(#"C:\WMdownloads\AdrenalineRush.wmv");
Job job = new Job();
job.MediaItems.Add(src);
job.ApplyPreset(Presets.VC1WindowsMobile);
job.OutputDirectory = #"C:\EncodedFiles";
job.Encode();

I don't think there are any classes in the .Net Framework which deal with transcoding WMV files.
But you can install the Windows Media 9 Encoder SDK and create appropriate objects in C# to do the conversion. See CodeProject.com - Convert MP3, MPEG, AVI to Windows Media Formats for a starting point. Even though that link starts with non-WMV files, the Windows Media Encoder doesn't restrict the input file format (at least when I've used the VBScript encoding batch file).
N.B If you use the WM9Encoder on Vista or Win7, you may need the hotfix - see TechNet - issues in using Windows Media Encoder 9 Series on Windows 7