I have sound files in my document directory folder and i want to trim that sound file.
How to do that?
you can use Extended Audio File Services. have a look at the reference for ExtAudioFileRead & ExtAudioFileWrite (they have sample code) then you can open one audio file read it, trim it and then write the new one.go here http://developer.apple.com/library/ios/#documentation/MusicAudio/Reference/ExtendedAudioFileServicesReference/Reference/reference.html
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I'm building a tool to edit audio with the Web Audio API.
Here is where I'm stuck:
...
source
.connect(gainNode)
.connect(analyser)
.connect(analyser2)
.connect(audioCtx.destination);
};
What I've written (which ends with the code above) successfully allows the user to upload a file, apply effects, and listen to it on play(). How would I then allow the user to click a button to export the results to a WAV file?
I've tried several methods online that have not worked for my use case.
Please let me know if more code is needed. Thank you for taking a look!
If you want a WAV file, I think you have to do that yourself. WAV files are quite simple. In this case, you'll need to add either a ScriptProcessorNode or AudioWorkletNode just before the destination to capture all the audio and convert it to a WAV file that can be downloaded.
If a compressed file is ok, you can look into MediaRecorder to save the data for you.
I ended up solving this by writing an entirely different script to download the file using OfflineAudioContext.
My original script plays the audio with effects, and the second script downloads it with the same effects. Now to figure out why there is latency on the effects while using OfflineAudioContext.
I have some .m4a files that were captured from a radio broadcast stream. They are playable using mpd (an open source Music Playing Daemon for *nix), but iTunes won't open them (nor will several other music players that should be able to play .m4a files). When I looked at the file in hex format, and compared it to an .m4a file from iTunes, it appeared that the file from the broadcast stream did not have any header info.
So I figured I'd try prepending some header info to the file, to see if that would make it playable by these other players.
I've tried to read the technical doc about the .m4a file format to understand how the header is structured, but it's far too complex for me to follow (most of the doc is about the coding, which isn't pertinent to this). The header seems fairly simple, conceptually - I can see 4-character tags, variable length data, and there are presumably some length codes to allow these to be split apart. It doesn't seem to contain any significant data about the actual audio data (like its total length), making me hopeful that I might be able to get by by simply copying the header from an .m4a file and prepending it to these headerless files.
I'm unable, though, to manually parse (that is, reverse-engineer) the header in order to even experiment with this. Can someone describe how to identify a complete header at the front of a .m4a file?
I want to compile several video clips using Avisynth on a server. I generate the .avs file and let VirtualDubMod read the file.
How do I save the video read from VirtualDubMod to an avi file using the command line only? If I open VirtualDubMod then I can choose save as but I am putting this on a server so no GUI will be available and it should be automatic.
EDIT:
After looking some more I found this. Is this a recommended approach?
I have a playlist file which give me another playlist file which also give me another playlist file, continously.
How can I play this playlist file? and Where can I found the source of video?
For example, I have a playlist file. That is
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=355670
http://slive.ytn.co.kr:1935/live/ylive_0624_1.sdp/playlist.m3u8?wowzasessionid=195968950
If I access to http://slive.ytn.co.kr:1935/live/ylive_0624_1.sdp/playlist.m3u8?wowzasessionid=195968950, it give me other playlist files.
#EXTM3U
#EXT-X-ALLOW-CACHE:NO
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:894
#EXTINF:11,
media_894.ts?wowzasessionid=195968950
#EXTINF:10,
media_895.ts?wowzasessionid=195968950
#EXTINF:11,
media_896.ts?wowzasessionid=195968950
If I access to the results, it also give me playlist files.
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=373764
http://slive.ytn.co.kr:1935/live/ylive_0624_1.sdp/playlist.m3u8?wowzasessionid=1093961187
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=382539
http://slive.ytn.co.kr:1935/live/ylive_0624_1.sdp/playlist.m3u8?wowzasessionid=1566364859
etc...
Although I can play the url http://slive.ytn.co.kr:1935/live/ylive_0624_1.sdp/playlist.m3u8?wowzasessionid=195968950 in safari in my iphone, I want to play this url in my own iphone app.
How can I play m3u8 file extension by myself?
EDIT - May be a duplicate of this SO question but if you want to persist the file, you'll need to go the hard way listed below.
Easy way = Embed UIWebView in your app and initialize it with the url of the .m3u8 file. This will open up quicktime which understands m3u8 and it will play it as it downloads.
Hard way = manually create the request/responses for each part of the m3u8 session and then download each .ts file in turn from the playlist file. As you get each "chunk" of the video, write it to a file or memory, then append the next "chunk" after it. I've done this for a h.264 encoded .m4v file served as a m3u8 and it worked (my code is too ugly to paste) but the pseudocode is:
Fetch the m3u8, saving any cookies sent and any headers that may be important*
Parse the .m3u8 (the first file, with the #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=373764) and pull our the urls.
Fetch the playlist from one of the URLs in the .m3u8 file (being sure to keep any headers/cookies in the request that may be necessary)
Parse the playlist file, saving as much metadata as you need from the top part of the file, construct an absolute URL for each .ts path, then stuff it into an array.
Iterate over the array (again, being mindful of cookies/headers) and fetch the content of each .ts URL into a file.
Play the downloaded file with whichever Media Framework you choose (search SO for how to do this)
If you just need to play the files, go the easy route. If you need to persist them, you need to do the m3u8 dance.
*HTTP Scoop is invaluable for seeing how the m3u8 "protocol" works and for making sure you're request/response headers are accurate - http://tuffcode.com/
*I used vanilla NSURLConnection synchronous calls as my code was just a proof of concept, other network frameworks like AFNetworking will make this a lot easier.
I'm trying to stream audio in .m3u and would like to get the .mp3 components of the file. How would I go about parsing the .m3u?
Thanks in advance!
I'm afraid you can get nothing but filename from m3u file. Try opening it using any conventional text editor to see it.