On Wed, Dec 17, 2008 at 11:17:11AM +0100, Dimitrios Symeonidis wrote: > Hi Martin, I am trying to read a stereo wav file converted from an mp3 > using audacity on ubuntu, and I get the error > "RuntimeError: is not a valid wav file" > > I looked at the code > http://gnuradio.org/trac/browser/gnuradio/branches/releases/3.1/gnuradio-core/src/lib/io/gr_wavfile_source.cc?rev=7808 > and I can see that it comes from > if (!gri_wavheader_parse(d_fp, > d_sample_rate, > d_nchans, > d_bytes_per_sample, > d_first_sample_pos, > d_samples_per_chan)) > > how do you propose i create the wav file from mp3 on linux, in order to > have a valid wavheader?
Hi Dimitrios and whoever it may interest on the GR list, the gr_wav* blocks only accept WAV if: - They are uncompressed (RIFF/WAV supports some kind of compression) - Samples are saved as integers, 8 or 16 bit resolution - They must have a valid header (i.e. begin with 'RIFF....WAVEfmt ') The latter should not be a problem with any audio program, including audacity. I know audacity uses a proprietary floating point format internally, so possibly one of the first conditions was violated? An easy way to convert an mp3 to a GR-compatible WAV file is to use sox: $ sox infile.mp3 -2 outfile.wav The -2 switch converts the output to 16-bit samples. Hope this helps, Martin > thank you in advance for your help > > ps you might want to publish your answer to discuss-gnuradio for future > reference... -- Dipl.-Ing. Martin Braun Phone: +49-(0)721-608 3790 Institut fuer Nachrichtentechnik Fax: +49-(0)721-608 6071 Universitaet Karlsruhe (TH) http://www.int.uni-karlsruhe.de/
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