Hi, How's the testing going? I compressed 194 individual .wav files (totaling 8.54GB) which contained tracks ripped from many varied albums. I unflacced them and compared their md5 signature with the same from the original .wav. They were all perfect. I didn't use the -V option just in case of any chance of mis-reporting. I hope to test it with the complete collection of ~41GB uncompressed, but it's a matter of finding the time. I currently have these files compressed using shorten. I was interested in how much FLAC could improve on this. The figures for the files I processed are: wav shn flac GB 8.54 5.51 5.11 % 100 64.5 59.8 Extrapolating that over the ~41GB, means it looks like FLAC will save me ~2GB over shorten. BTW That's shorten 3.1 which puts the seek tables on the end of the .shn files. Are the .flac files seekable? Cheers. Mark Powell - UNIX System Administrator - The University of Salford Academic Information Services, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key
The occurances of "make" in the flac Makefile should be changed to "$(MAKE)". Not every system has GNU make called make. In fact it's probably only Linux that does. Cheers. Mark Powell - UNIX System Administrator - The University of Salford Academic Information Services, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key
Mark Powell
2004-Sep-10 16:45 UTC
[Flac-dev] Re: flac and pipes problems (was: Possible bug)
Hi, I note that shorten does transfer across any extraneous data after the wav chunks, making the wav file after being shortened exactly the same as before. Could flac not easily do this? Simple copy? At least by default with a flag to specify if you don't want extraneous data transferred across? Also, when flac takes input from stdin it fails to fill in the wav size fields correctly, whereas shorten has no problems with this: i.e. $ md5 mj.wav MD5 (mj.wav) = c89a865943f32eacb819ad208c6669ae $ shorten31 mj.wav - | shorten -x - - | md5 c89a865943f32eacb819ad208c6669ae $ flac -fw mj.wav - | flac -d -fw - - | md5 43e1e8e2f800a1d9a991be8e30e902c9 $ flac -fw mj.wav - | flac -d -fw - - | hd | head -4 00000000 52 49 46 46 24 00 00 00 57 41 56 45 66 6d 74 20 |RIFF$...WAVEfmt | 00000010 10 00 00 00 01 00 02 00 44 ac 00 00 10 b1 02 00 |........D?...?..| 00000020 04 00 10 00 64 61 74 61 00 00 00 00 02 00 f6 ff |....data......??| 00000030 03 00 f5 ff 03 00 f5 ff 03 00 f5 ff 02 00 f5 ff |..??..??..??..??| You can see it puts a data chunk size of zero in there. Flac refuses completely to encode from a pipe. Again, shorten has no problems with both these examples: $ shorten - mj.shn < mj.wav $ cat mj.wav | shorten - mj.shn Flac handles stdin being a file, but the pipe throws it: $ flac - mj.flac < mj.wav $ cat mj.wav | flac -fw - mj.flac ERROR seeking while skipping samples in input file - Cheers. On Fri, 5 Jan 2001, Mark Powell wrote:> Hi, > I have a large wav file generated by SoundForge. The last 176bytes of > the file are some sort of comment inserted by SoundForge. The length field > in the wav "data" chunk correctly specify the data length as: > > <file-size> - (full wav header size) 44 - 176 > > However, flac seems to ignore this and compresses the comment along with > the wav data. When unflacced back to wav the length field in the data > chunk now specifies: > > <file-size> - 44 > > It's lost the fact that the last 176 bytes are not actually part of the > audio. If it's not possible to carry this comment into the flac format > then it should be dropped rather than encoded as audio? > Cheers. > > BTW It compressed the 350MB wav file perfectly at level 8. > > Mark Powell - UNIX System Administrator - The University of Salford > Academic Information Services, Clifford Whitworth Building, > Salford University, Manchester, M5 4WT, UK. > Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key > > > _______________________________________________ > Flac-dev mailing list > Flac-dev@lists.sourceforge.net > http://lists.sourceforge.net/mailman/listinfo/flac-dev >Mark Powell - UNIX System Administrator - The University of Salford Academic Information Services, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key
Hi, I have a large wav file generated by SoundForge. The last 176bytes of the file are some sort of comment inserted by SoundForge. The length field in the wav "data" chunk correctly specify the data length as: <file-size> - (full wav header size) 44 - 176 However, flac seems to ignore this and compresses the comment along with the wav data. When unflacced back to wav the length field in the data chunk now specifies: <file-size> - 44 It's lost the fact that the last 176 bytes are not actually part of the audio. If it's not possible to carry this comment into the flac format then it should be dropped rather than encoded as audio? Cheers. BTW It compressed the 350MB wav file perfectly at level 8. Mark Powell - UNIX System Administrator - The University of Salford Academic Information Services, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key