history.html

mp3的经典 压缩 和 解压缩 源码。

  <li> <font color="#ff0000">Expermental subblock gain code enabled with -Z.</font></li>
  <li> New "-r" option for raw pcm input files.&nbsp; With -r, LAME will not do 
    any fseek()'s or look for wav and aiff headers on the input file.</li>
  <li> Bug fixes in mp3x (frame analyzer) for viewing frames near end of the file.</li>
  <li> Bug fixed to allow setting the sampling rate of raw pcm input files.</li>
</ul>
<h3> LAME 3.20beta&nbsp; July 19 1999</h3>
<ul>
  <li> Bug in get_audio.c fixed.&nbsp; Libsndfile wrappers would not compile (Miguel 
    Revilla&nbsp; Rodriguez)</li>
  <li> Nils Faerber found some unitialized variables and some wierd extranous 
    computations in filter_subband, now fixed.&nbsp; This was causing seg faults 
    on some machines.</li>
  <br>
  &nbsp; 
</ul>
<h3> LAME 3.19beta&nbsp; July 18 1999</h3>
<ul>
  <li> <font color="#ff0000">Oops!&nbsp; Robert Hegemann immediatly found a bug 
    in the new&nbsp; (old -Z option) quantization code.&nbsp; calc_noise1 was 
    not returning tot_noise, so non ms-stereo frames were buggy.</font></li>
  <br>
  &nbsp; 
</ul>
<h3> LAME 3.18beta&nbsp; July 17 1999</h3>
<ul>
  <li> <font color="#ff0000">Many psycho-acoustic bug fixes.&nbsp; Dan Nelson 
    discovered a bug in MPEG2: For short blocks, the code assumes 42 partition 
    bands.&nbsp; MPEG1 sometimes has less, MPEG2 can have more.&nbsp; In MPEG1, 
    this bug would not have effected the output if your compiler initializes static 
    variables to 0 on creation.&nbsp; In MPEG2 it leads to array out-of-bounds 
    access errors. Finally, there was a related bug in MPEG1/MPEG2, short &amp; 
    long blocks where the energy above 16 kHz was all added to partition band 
    0. (the lowest frequeny partition band!)</font></li>
  <li> <font color="#ff0000">The -Z option (Gabriel Bouvigne's idea of using total 
    quantization noise to choose between two quantizations with the same value 
    of "over") is now the default.&nbsp; I believe this helps remove the trilling 
    sound in Jan's testsignal4.wav.&nbsp; The quality of testsignal2.wav and testsignal4.wav 
    are now better than Xing and getting closer to FhG.</font></li>
  <li> Bug fixes in frame &amp; sample count for downsampling mode. (ben "jacobs")</li>
  <li> Patches to improve modulization.&nbsp; (ben "jacobs")</li>
</ul>
<h3> LAME 3.17beta&nbsp; July 11 1999</h3>
<ul>
  <li> substantial code cleanup towards goal of making LAME more modular.</li>
</ul>
<h3> LAME 3.16beta&nbsp; July 11 1999</h3>
<ul>
  <li> <font color="#ff0000">New tunings of window switching, and better bit allocation 
    based on pe.&nbsp; (Jan Rafaj.&nbsp; improves both testsignal2.wav and testsignal4.wav).</font></li>
  <li> <font color="#ff0000">Bug in mid/side quantization when side channel was 
    zero fixed.&nbsp; (Albert Faber)</font></li>
  <li> Removed some extranous computations in l3psy.c (Robert Hegemann)</li>
  <li> More detailed timing status info, including hours display. (Sakari Ailus) 
    and percentage indicator (Conrad Sanderson).</li>
  <li> <font color="#3366ff">Window_subband and calc_noise1,calc_noise2 speedups.&nbsp; 
    Quantize_xrpow speedup should be significant on non GNU/intel systems. (Mike 
    Cheng)</font></li>
  <li> <font color="#3366ff">Better initial guess for VBR bitrate.&nbsp; Should 
    speed up VBR encoding.&nbsp; (Gabriel Bouvigne)</font></li>
  <li> More advanced .wav header parsing.&nbsp; fixes bugs involving click in 
    first frame. (Robert.Hegemann)</li>
  <li> Correct filesize and total frame computation when using LIBSNDFILE (ben 
    "jacobs")</li>
  <li> Click in last frame (buffering problem) when using libsndfile fixed.</li>
  <li> Audio I/O code overhauled.&nbsp; There is now a uniform audio i/o interface 
    to libsndfile or the LAME built in wav/aiff routines.&nbsp; All audio i/o 
    code localized to get_audio.c.</li>
  <br>
  &nbsp; 
</ul>
<h3> LAME 3.15beta</h3>
<ul>
  <li> times()/clock() problem fixed for non-unix OS.&nbsp; (Ben "Jacobs")</li>
  <li> Fixed uninitialized pe[] when using fast mode.&nbsp; (Ben "Jacobs")</li>
</ul>
<h3> LAME 3.13&nbsp; June 24 1999</h3>
<ul>
  <li> Patches for BeOS from Gertjan van Ratingen.</li>
  <li> Makefile info for OS/2 Warp 4.0&nbsp; (from dink.org).</li>
  <li> Status display now based on wall clock time, not cpu time.</li>
  <li> mem_alloc no longer allocates twice as much memory as needed (Jan Peman).</li>
</ul>
<h3> 3.12pre9</h3>
<ul>
  <li> Updated BLADEDLL code to handle recent changes (Albert Faber).</li>
  <li> Bug fixed in parsing options when not using GTK (Albert Faber).</li>
  <li> <font color="#ff0000">MPEG2 Layer III psycho acoustics now working.</font></li>
  <li> <font color="#3366ff">Improved huffman encoding Chris Matrakidis. (10% 
    faster).&nbsp; I dont know how he finds these improvements!&nbsp; LAME with 
    full quality now encodes faster than real time on my PII 266.</font></li>
  <li> Fixed time display when encoding takes more than 60 minutes.</li>
</ul>
<h3> 3.12pre8</h3>
<ul>
  <li> <font color="#ff0000">New <a href="gpsycho/ms_stereo.html">mid/side stereo</a> 
    criterion.&nbsp; LAME will use mid/side stereo only when the difference between 
    L &amp; R masking thresholds (averaged over all scalefactors) is less then 
    5db.&nbsp; In several test samples it does a very good job mimicking the FhG 
    encoder.</font></li>
  <li> <font color="#ff0000">Bug in mid/side stereo fixed:&nbsp; independent variation 
    of mid &amp; side channel scalefactors disabled.&nbsp; Because of the way 
    outer_loop is currently coded, when encoding mid/side coefficietns using left/right 
    thresholds, you have to vary the scalefactors simultaneously.</font></li>
  <li> <font color="#ff0000">Bug in side/mid energy ratio calculation fixed. (Thanks 
    to Robert Hegemann)</font></li>
  <li> Default mode is stereo (not jstereo) if bitrate is chosen as 192kbs or 
    higher.&nbsp; Tero Auvinen first pointed out that FhG seems to think at 160kbs, 
    their encoder is so good it doesn't need jstereo tricks. Since LAME is not 
    as good as FhG, I am going to claim that 192kbs LAME is so good it doens't 
    need jstereo tricks, and thus it is disabled by default.</li>
  <li> WAV header parsing for big-endian machines, and automatic detection of 
    big-endian machines.&nbsp; (Thanks to&nbsp; Sigbj&oslash;rn Skj&aelig;ret).</li>
  <li> added 56 sample delay to sync LAME with FhG.</li>
  <li> MP3x (frame analyzer) can now handle MPEG2 streams.</li>
</ul>
<h3> 3.12pre7</h3>
<ul>
  <li> MPEG2 layer III now working!&nbsp; lower bit rates (down to 8kbs) and 3 
    more sampling frequencies:&nbsp; 16000, 22050, 24000Hz. Quality is poor - 
    the psy-model does not yet work with these sampling frequencies.</li>
  <li> Fixed "ERROR: outer_loop(): huff_bits &lt; 0." bug when using VBR.</li>
  <li> bash and sh scripts to run LAME on multiple files now included.&nbsp; (from 
    Robert Hegemann and Gerhard Wesp respectively)</li>
  <li> bug fix in encoding times for longer files from&nbsp; (Alvaro Martinez 
    Echevarria)</li>
  <li> yet another segfault in the frame analyzer fixed.</li>
  <li> ISO psy-model/bit allocation routines removed.&nbsp; This allowed makeframe() 
    to be made much simpler, and most of the complicated buffering is now gone. 
    Eventually I would like the encoding engine to be a stand alone library.</li>
</ul>
<h3> 3.12pre6</h3>
<ul>
  <li> <font color="#ff0000">Better VBR tuning.&nbsp; Find minimum bitrate with 
    distortion less than the allows maximum.&nbsp; A minimum bit rate is imposed 
    on frames with short blocks (where the measured distortion can not be trusted).&nbsp;&nbsp; 
    A minimum frame bitrate can be specified with -b, default=64kbs.</font></li>
  <li> <a href="http://www.zip.com.au/%7Eerikd/libsndfile">LIBSNDFILE</a> support.&nbsp; 
    With libsndfile, LAME can encode almost all sound formats.&nbsp; Albert Faber 
    did the work for this, including getting libsndfile running under win32.</li>
  <li> CRC checksum now working!&nbsp;&nbsp; (Thanks to Johannes Overmann )</li>
  <li> frame analyzer will now work with mono .mp3 files</li>
  <li> <font color="#3366ff">more code tweeks from Jan Peman.</font></li>
  <li> <font color="#3366ff">Compaq-Alpha(Linux) fixes and speedups from Nils 
    Faerber.</font></li>
  <li> <font color="#3366ff">Faster bin_search_StepSize from Juha Laukala.</font></li>
  <li> <font color="#3366ff">Faster quantize() from Mike Cheng</font></li>
  <li> <font color="#3366ff">Faster quantize_xrpow() from Chris Matrakidis.&nbsp; 
    xrpow_flag removed since this option is now on by default.</font></li>
  <li> Fixed .wav header parsing from Nils Faerber.</li>
  <li> Xing VBR frame info header code from Albert Faber.&nbsp;&nbsp; "Xing" and 
    "LAME 3.12" embedded in first frame.</li>
  <li> <font color="#ff0000">Bug in VBR bit allocation based on "over" value fixed.</font></li>
</ul>
<h3> LAME 3.11&nbsp; June 3 1999</h3>
<ul>
  <li> Almost all warnings (-Wall) now fixed!&nbsp; (Thanks to Jan Peman)</li>
  <li> More coding improvements from Gabriel Bouvigne and Warren Toomey.</li>
  <li> <font color="#ff0000">VBR&nbsp; (variable bit rate).&nbsp;&nbsp; Increases 
    bit rate for short blocks and for frames where the number of bands containing 
    audible distortion is greater than a given value.&nbsp; Much tuning needs 
    to be done.</font></li>
  <li> Patch to remove all atan() calls from James Droppo.</li>

</ul>
<h3> LAME 3.10 May 30 1999</h3>
<ul>
  <li> <font color="#3366ff">Fast mode (-f)&nbsp; disables psycho-acoustic model 
    for real time encoding on older machines.&nbsp; Thanks to Lauri Ahonen who 
    first sent a patch for this.</font></li>
  <li> <font color="#ff0000">New bit reservoir usage scheme to accommodate the 
    new pre-echo detection formulas.</font></li>
  <li> <font color="#ff0000">Tuning of AWS and ENER_AWS pre-echo formulas by Gabriel 
    Bouvigne and myself.&nbsp; They work great!&nbsp; now on by default.</font></li>
  <li> In jstereo, force blocktypes for left &amp; right channels to be identical.&nbsp; 
    FhG seems to do this.&nbsp; It can be disabled with "-d".</li>
  <li> Patches to compile MP3x under win32 (Thanks to Albert Faber).</li>
  <li> <font color="#3366ff">bin_serach_stepsize limited to a quantizationStepSize 
    of&nbsp; -210 through 45.</font></li>
  <li> <font color="#ff0000">outer_loop()&nbsp; will now vary Mid &amp; Side scalefactors 
    independently.&nbsp; Can lead to better quantizations, but it is slower (twice 
    as many quantizations to look at).&nbsp; Running with "-m f" does not need 
    this and will run at the old speed</font></li>
  <li> <font color="#ff0000">Bug in inner_loop would allow quantizations larger 
    than allowed.&nbsp; (introduced in lame3.04, now fixed.)</font></li>
  <li> Updated HTML documentation from Gabriel Bouvigne.</li>
  <li> Unix&nbsp; man page from William Schelter.</li>
  <li> <font color="#ff0000">numlines[] bug fixed.&nbsp; (Thanks to Rafael Luebbert, 
    MPecker author).</font></li>
  <li> <font color="#3366ff">Quantization speed improvements from Chirs Matrakidis.</font></li>
  <li> <font color="#ff0000">When comparing quantizations with the same number 
    of bands with audible distortion, use the one with the largest scalefactors, 
    not the first one outer_loop happened to find.</font></li>
  <li> Improved defination of best quantization when using -f (fast mode).</li>
  <li> subblock code now working.&nbsp; But no algorithm to choose subblock gains 
    yet.</li>
  <li> Linux now segfaults on floating point exceptions.&nbsp; Should prevent 
    me from releasing binaries that crash on other operating systems.</li>
</ul>
<h3> LAME 3.04 May 22 1999</h3>
<ul>
  <li>Preliminary documentation from Gabriel Bouvigne.</li>
  <li> <font color="#3366ff">I wouldn't have thought it was possible, but now 
    there are even more speed improvements from Chris Matrakidis!&nbsp; Removed 
    one FFT when using joint stereo, and many improvements in loop.c.</font></li>
  <li> "Fake" ms_stereo mode renamed "Force" ms_stereo since it forces mid/side 
    stereo on all frames.&nbsp; For some music this is said to be a problem, but 
    for most music mode is probably better than the default jstereo because it 
    uses specialized mid/side channel masking thresholds.</li>
  <li> Small bugs in Force ms_stereo mode fixed.</li>
  <li> Compaq Alpha fixes from Nathan Slingerland.</li>
  <li> <font color="#ff0000">Some new experimental pre-echo detection formulas 
    in l3psy.c (#ifdef AWS and #ifdef ENER_AWS, both off by default.&nbsp; Thanks 
    to Gabriel Bouvigne and Andre Osterhues)</font></li>
  <li> Several bugs in the syncing of data displayed by mp3x (the frame analyzer) 
    were fixed.</li>
  <li> highq (-h) option added.&nbsp; This turns on things (just one so far) that 
    should sound better but slow down LAME.</li>
</ul>
<h3>LAME 3.03 May 18 1999 </h3>
<ul>
  <li> <font color="#3366ff">Faster (20%) &amp; cleaner FFT (Thanks to Chris Matrakidis&nbsp; 
    http://www.geocities.com/ResearchTriangle/8869/fft_summary.html)</font></li>
  <li> mods so it works with VC++ (Thanks to Gabriel Bouvigne, www.mp3tech.org)</li>
  <li> MP3s marked "original" by default&nbsp; (Thanks to Gabriel Bouvigne, www.mp3tech.org)</li>
  <li> Can now be compiled into a BladeEnc compatible .DLL&nbsp;&nbsp; (Thanks 
    to&nbsp; Albert Faber, CDex author)</li>
  <li> Patches for "silent mode" and stdin/stdout&nbsp; (Thanks to Lars Magne 
    Ingebrigtsen)</li>
  <li> <font color="#ff0000">Fixed rare bug: if a long_block is sandwiched between 
    two short_blocks, it must be changed to a short_block, but the short_block 
    ratios have not been computed in l3psy.c.&nbsp; Now always compute short_block 
    ratios just in case.</font></li>
  <li> <font color="#ff0000">Fixed bug with initial quantize step size when many 
    coefficients are zero.&nbsp; (Thanks to