Not all the MP3s I am using are mono, and encoding them all as mono is not a valid approach for the project I am working on.
MP3 is a streaming media format, where the audio is split into distinct frames that can be individually decoded and played. It is specifically designed to allow an MP3 player to synchronise and start playing in the middle of an MP3 stream. The headers that you are talking about may be ID3v1 tags, which are placed at the end of an MP3 file, and may have interferred in the concatenation. I am specifically only using ID3v2 tags, which have no problem working in streaming (and therefore concatenated) MP3s. John Steve Swinsburg wrote: > Correct me if I'm wrong, but you cant simply just concatenate mp3s > together to form one big mp3. Even though you have them in consistent > formats, you'll run in to problems with the header blocks being repeated > over and over for the various different mp3s. > > Unless you use some sort of library which can join mp3s *properly* then > I'm not sure how it'll be done. I've tried the same thing using a Perl > library, but with no success... the purpose was to put a standard > copyright notice on the front of each mp3 and then apply the tags, but it > didn't work properly. > Unless there is a way to call Lame on the commandline and get it to ONLY > write the tags, then I couldn't do it. > > If you are able to successfully cat these files together and sort out the > headers properly, I'd love to hear about it! Plus what you used to do it. > > Although as another poster said, you are probably best having all your > files in mono, catting them together, then just duplicating the one > channel to a stereo channel... Although it will still be mono, just a > stereo mono, wouldnt it? > > Good luck :) > > > > >>I understand the problems that can occur when applying a lossy >>compression technique twice - however this is a requirement of the >>project that I am working on. >> >>The point of standardising all our MP3s to 128kbps 44.1khz joint stereo >>is that we can then simply concatenate them together to create an MP3 >>stream. I am unsure what we would officially need to do according to the >>MP3 specifications, but experimentation with some important (for our >>project) MP3 players like iTunes has shown us that all of these >>parameters need to be the same before the concatenation is successfully >>played. >> >>Besides this reason, I just think that the lame command line interface >>ought to do what it's asked, or report an error. If I tell it to encode >>as joint stereo and it encodes as mono, I would consider that a bug. >> >>John >> >>tech list wrote: >> >>>Fix may be valid, but what exactly does it serve? There cannot be any >>>improvement in quality, rather it may detiriorate (due to re-encoding). >>>If >>>you >>>want to change a mono file to stereo - maybe to create a pseudo-stereo >>>effect, use the decoded output, and duplicate it into left & right >>>channels. >>> >>>On 5/13/06, Robert Hegemann <[EMAIL PROTECTED]> wrote: >>> >>> >>>>Am Donnerstag, 11. Mai 2006 10:56 schrieb John Snelson: >>>> >>>> >>>>>I'm trying to change a variety of MP3s into a standard 128kbps 44.1khz >>>>>joint stereo MP3. Most of this works great with the Lame command line >>>>>front end - unless the input MP3 is already mono. In that case, Lame >>>>>chooses to output a mono MP3, even if I explicitly specify a "-m j" >>>> >>>>option. >>>> >>>>1. transcoding from mp3 to mp3 isn't a good idea, take the original PCM >>>>files >>>>2. there is no sense in encoding mono files as joint stereo, but with >>>>one >>>> exception: working around a buggy mp3 device >>>> >>>> >>>>Ciao Robert >>>>_______________________________________________ >>>>mp3encoder mailing list >>>>[email protected] >>>>https://minnie.tuhs.org/mailman/listinfo/mp3encoder >>>> >>> >>>_______________________________________________ >>>mp3encoder mailing list >>>[email protected] >>>https://minnie.tuhs.org/mailman/listinfo/mp3encoder >> >> >>-- >>John Snelson, XML Consultant +44-1865-811184 >>Parthenon Computing Ltd http://blog.parthcomp.com/dbxml >>_______________________________________________ >>mp3encoder mailing list >>[email protected] >>https://minnie.tuhs.org/mailman/listinfo/mp3encoder >> > > > > _______________________________________________ > mp3encoder mailing list > [email protected] > https://minnie.tuhs.org/mailman/listinfo/mp3encoder -- John Snelson, XML Consultant +44-1865-811184 Parthenon Computing Ltd http://blog.parthcomp.com/dbxml _______________________________________________ mp3encoder mailing list [email protected] https://minnie.tuhs.org/mailman/listinfo/mp3encoder
