How to programmatically convert .rm (RealPlayer Media) file to MP3 or another format? - audio

I would like to convert .rm (RealPlayer Media) file to MP3 or another format?
First, I successfully managed that using VLC but the quality was not good. Then I tried the Real Alternative codec with DirectShow, this also worked ok, but then I found that the codec is no longer developed because RealNetworks sued the developer.
Now, I have installed the RealPlayer and I am trying to use it's DirectShow filters to convert .rm to .mp3 but without success:( (Actually after adding RealPlayer Transcode filter and choosing a file the GraphStudio crashes.)
Is there a legal way to programmatically convert .rm file to another format? How to make RealPlayer to programmatically convert files? Do you have any hints or examples, how to use RealPlayer Transcode filter? (I am new to DirectShow.)
UPDATE to make the question more concrete: How can I list implemented interfaces and its members of RealPlayer Transcode filter? I have not found any documentation:( (The GraphStudio says it has 0 pins and just common properties.)

You need to build a DirectShow graph to read and decode .rm, then compress audio into MP3 and write it into a file. This is similar to recompressing an AVI file, described in some detail on MSDN: Recompressing an AVI File. You just have audio without video there, and the container formats are different.
UPDATE: There is no way to reliably list implemented interfaces in COM. Sometimes you can find this out by checking the type library, however a lot of DirectShow filters are coming without it. Typically, you need an SDK header file from the filter vendor to get a definition of implemented so called 'private' interfaces.

Related

How to write a webm (or other) audio/video block of data from MediaRecorder to a properly formatted .webm (or other) container file?

I am using javascript to capture audio data from MediaRecorder, and base64 encode it so I can send it back to the web server where it can be saved for later playback.
data:audio/webm;codecs=opus;base64,GkXfo59ChoEBQveBA...(too much data to post, but you get the idea)
I can put that data into an HTML5 audio element's .src field, and play it back on a Chrome browser just fine. But Safari can't handle the data in that format, I guess it doesn't support the opus codec.
One solution for me would be to figure out how to write the audio data into a properly formatted .webm container file, and then use ffmpeg.exe to convert it to some other Safari friendly format.
But I don't know the file format for .webm file - I'm looking for tips or guidance how to write such a .webm file.
Anybody have any suggestions, libraries, or tips to write data like above to a .webm file? I prefer a C# .net answer, but javascript will also do, or any examples are appreciated.
Well, I got a tip from smart developer (earnabler) that if I stripped off the header portion of the content:
"data:audio/webm;codecs=opus;base64,"
and decoded just the base64 portion:
"GkXfo59ChoEBQveBA...(too much data to post, but you get the idea)"
...back to binary (example in C#):
byte[] decodedBinaryData;
decodedBinaryData = Convert.FromBase64String(encodedBase64String);
...and wrote that binary to a file with a matching file extension (.webm in this example), that the file would be a properly formatted file of that type understandable by other media software.
Lo and behold, it was! I could play the file in MediaPlayer, or QuickTime, or whatever, and could use FFMPEG to convert it to other types.
So that gives me a pathway to save/use/convert the media in many ways. Problem solved.

Need a way to write headers on a wav file generated by sox

I'm using sox to convert some mp3 files to wav for a project. The problem is that the software that plays the files does not have the media name for the element it is playing. I can't seem to find a win32 cli tool to read the header of the wav file and write what I need to it.
Sox will read the header but it's not showing the title of the media element that was inserted with the old software I used. I just couldnt automate it or I would have used it instead.
I have determined the info is written in either CART CHUNK section or just to the file headers. I can't figure out to write my own data there.
The way I was able to do this was with this project: https://github.com/JamesHeinrich/getID3

Is it possible to add custom metadata tags to music files?

I am working on a music player application and I'm not happy with the current standard for music tags. I would like to extend on the current ones. Is it possible to add custom metadata tags to audio files (MP3, OGG, FLAC, WAV)? Obviously only my application could read this metadata. Would adding custom metadata corrupt the files so they can't be played correctly by other players?
Yes, most tagging formats support custom tags.
ID3 allows TXXX.
FLAC and Vorbis Comments both allow tags with any name (it's not really prescribed in the same way ID3 is).
You can do it with MP4 if you use XMP to contain the tags: How can I embed metadata into a custom XMP field with exiftool?
Any other software that cannot work because a custom tag is set has bigger problems!

Rebuilding MP4 file from fragmented MP4 "mdat" atom?

I'm trying to rebuild a video file from a Smooth Streaming server. Smooth Streaming serves fMP4 files which are regular MP4 files without neither their FTYP nor their MOOV atoms.
All the informations stored in those atom are placed into a Manifest XML file, which I have.
Is there a way to programmatically rebuild the original MP4 file, either by:
rebuilding a new file straight from H264/AAC content located in MDAT
(and picture format infos); or
rebuilding FTYP and MOOV atoms
Or else, is there a tool which can merge fMP4?
Yes. It is completely possible.
You can do this with FFmpeg. Study the mov.c [MP4 demuxer] from libavformat.
You will need to complete the MP4 in memory with all data that is "missing" in the fMP4. In other words, when you need an atom that doesn't exist in fMP4 [almost all], you will have to input all information hard-coded (such information, most of them come from the manifest).
It's not easy... but for sure it's possible. I've done by myself. Unfortunately the code is not my property.
Good luck! ;-)
UPDATE: the PIFF format specification will be very useful (http://go.microsoft.com/?linkid=9682897) so one can understand what is already in the fMP4 and what is not!
It is simple to rebuild a mp4 file, if there are ism and ismc file which are related to fragmented mp4 files.
It is requested that you should know media type, codec type, codec specific data and time scale of each trak to rebuild a moov and ftyp atom.
these information can be retrieved from ism and ismc file.
you can retrieve a media type of each track from the ism file.
you can retrieve codec type, codec specific data and time scale of each track from the ismc file.
simply speaking, ism/ismc files are meta data for server and client so that you can rebuild meta data(ftyp, moov atom) for a mp4 file.

how to write mpeg4 file in vc++ directshow

hai..
Am writing application for capture video from camera in vc++ using directshow and write that
file in WMV format.and how to write MPEG4 file format.can i install any sdk for mpeg4.can you provide details about mpeg file writing in vc++
kindly help me
thanks
I'm not entirely clear if you want to change the video format or just the container format. If you just want to write the existing camera output into a different container file, then you need a multiplexor filter. There's an MP4 multiplexor filter available in source form at www.gdcl.co.uk/mpeg4. If you connect your camera's output to this filter and then the file writer, you should be ok.
If, on the other hand, you need to encode the camera output to mpeg-4 video as well, then I think you will need to licence a third-party encoder filter.
G

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