Trim Audio File
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I need to trim down size/duration of an audio file, for example I have a 5 MB audio file and I want to create an audio file having only 1 MB of size or 60 seconds of duration.
So to do this I need to first decode original audio file completely/partially and then encode the raw samples again until it reaches 1MB/60 sec.
Is there any other optimized way ? For example playing with audio headers.
-- Regards, Sudarshan Bisht _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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What muxer/codec do your audio files use?
On Thu, Oct 6, 2011 at 3:35 AM, Sudarshan Bisht <[hidden email]> wrote: > I need to trim down size/duration of an audio file, for example I have a 5 > MB audio file and I want to create an audio file having only 1 MB of size or > 60 seconds of duration. > So to do this I need to first decode original audio file > completely/partially and then encode the raw samples again until it reaches > 1MB/60 sec. > Is there any other optimized way ? For example playing with audio headers. > > > -- > Regards, > > Sudarshan Bisht > > _______________________________________________ > gstreamer-devel mailing list > [hidden email] > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel > > -- http://codebad.com/ _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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In reply to this post by Sudarshan Bisht
Hi,
On Thu, Oct 6, 2011 at 3:35 AM, Sudarshan Bisht <[hidden email]> wrote: > I need to trim down size/duration of an audio file, for example I have a 5 > MB audio file and I want to create an audio file having only 1 MB of size or > 60 seconds of duration. There's a (AFAIK closed source) tool out there called mp3DirectCut that does this *without* reencoding (so you don't suffer any quality degradation at all): http://mpesch3.de1.cc/mp3dc.html Not sure if there's an element out there for gstreamer that does similar. And I have no idea if this is even theoretically possible with other audio codecs. But at least for mp3, you should be able to write a gstreamer element to do it without re-encoding, in the worst case. > So to do this I need to first decode original audio file > completely/partially and then encode the raw samples again until it reaches > 1MB/60 sec. Try to avoid this, unless your encoded format is lossless (WAV, FLAC). Re-encoding using lossy encoders is like making a photocopy of a previously photocopied document: each time you do it, the quality degrades slightly. > Is there any other optimized way ? For example playing with audio headers. If you do modify the headers to reflect a different duration, you will want to also get rid of the extraneous data, to keep your file compliant with the file format (just speaking in general here). It's not a good idea to lie about the duration while keeping the actual data intact; plus it wastes storage. If you're going to do this, then do it by cutting the data out, too. Many frame-based codecs should theoretically have a way for a program to automatically chop some samples out of it without re-encoding.... the challenge is finding or writing software to do what you're looking for with the file formats you'll be using. HTH, Sean > > > -- > Regards, > > Sudarshan Bisht > > _______________________________________________ > gstreamer-devel mailing list > [hidden email] > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel > > gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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In reply to this post by Sudarshan Bisht
On Thu, Oct 6, 2011 at 1:05 PM, Sudarshan Bisht
<[hidden email]> wrote: > I need to trim down size/duration of an audio file, for example I have a 5 > MB audio file and I want to create an audio file having only 1 MB of size or > 60 seconds of duration. > So to do this I need to first decode original audio file > completely/partially and then encode the raw samples again until it reaches > 1MB/60 sec. > Is there any other optimized way ? For example playing with audio headers. > Not sure if your end goal is something like "Audio thumbnails" e.g. fixed size/duration audio samples, but if it is, you'd find some good clues in here http://www.patentstorm.us/patents/7386357.html But then, you see, it is patented :-). Never the less, you'd note that fixed size, from the beginning of an audio file isn't a good idea, for example if vocals do not even start in the first 60 mins of a song (e.g. a song thumbnail/sampler). the "mad" element has a src query API that seems to permit determining the position, length -- which might come in handy to raise an event when you reach a certain position in the file, s.t. you terminate dumping it to file, and quit pipeline. This is coming from someone who has spent a very little time, that too only recently with gstreamer, and not very familiar with the API. And then you have this http://mp3splt.sourceforge.net/mp3splt_page/home.php _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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Thanks all for your suggestions.
On Thu, Oct 6, 2011 at 9:18 PM, Icarus Alive <[hidden email]> wrote:
Regards, Sudarshan Bisht _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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