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libmad - MPEG audio decoder library Copyright (C) 2000-2004 Underbit Technologies, Inc.
$Id: CHANGES,v 1.14 2004/02/17 02:02:03 rob Exp $
===============================================================================
Version 0.15.1 (beta)
* Updated to autoconf 2.59, automake 1.8.2, libtool 1.5.2.
* Replaced Layer III IMDCT routine with one based on a faster algorithm, improving both speed and accuracy.
* Improved portability of the Huffman table initialization.
* Fixed a problem that could result in an assertion failure in layer3.c due to an invalid Layer III free format bitrate.
* Improved the robustness of Layer II bitrate/mode combinations, and added a new MAD_ERROR_BADMODE error enum. The allowability of low-bitrate stereo streams is influenced by the --enable-strict-iso option to `configure'.
Version 0.15.0 (beta)
* Updated to autoconf 2.57, automake 1.7.5, libtool 1.4.3.
* Added new mad_f_div() API routine.
* Added a 64th entry to the Layer I/Layer II scalefactor table, for better compatibility with existing streams. The --enable-strict-iso option to `configure' can be used to disable use of this entry.
* Modified the header decoding routine to allow the reserved emphasis value, for better compatibility with existing streams. The --enable-strict-iso option to `configure' can be used to restore the previous behavior of reporting this value as an error.
* Added new MAD_EMPHASIS_RESERVED enumeration constant.
* Fixed a bug in the ARM version of mad_f_scale64() discovered by Andre McCurdy.
* Rewrote PowerPC assembly for minor gains.
* Modified mad_timer_fraction() to avoid the possibility of division by zero when 0 is passed as the second argument.
* Fixed a non-fatal problem caused by attempting to designate ancillary bits in Layer III after a decoding error.
* Changed to build a shared library by default.
* Changed to use native Cygwin build by default; give --host=mingw32 to `configure' to use MinGW (and avoid a dependency on the Cygwin DLL).
Version 0.14.2 (beta)
* Changed Cygwin builds to use MinGW; resulting Win32 executables no longer have a dependency on Cygwin DLLs.
* Added a new mad_stream_errorstr() API function to libmad for retrieving a string description of the current error condition.
Version 0.14.1 (beta)
* Updated config.guess and config.sub to latest upstream versions.
* Enabled libtool versioning rather than release numbering.
* Improved the documentation in minimad.c.
* Several other small fixes.
Version 0.14.0 (beta)
* Added a 64-bit FPM negation operation to improve performance of subband synthesis on some platforms.
* Improved MSVC++ portability and added MSVC++ project files.
* Added rounding to Layer III requantization for slightly better accuracy.
Version 0.13.0 (beta)
* Ancillary data is now properly extracted from Layer III streams.
* Rewrote the Layer III joint stereo decoding routine to correct a major MPEG-2 problem and a minor MPEG-1 problem decoding intensity stereo.
* Eliminated the dependency on sign-extending right shifts for Layer I and Layer II.
* Renamed `private' field to `private_bits' for better C++ compatibility.
* Gratuitously renamed `sfreq' field to `samplerate' and MAD_ERROR_BADSAMPLEFREQ constant to MAD_ERROR_BADSAMPLERATE.
* Added `samplerate' and `channels' fields to synth.pcm struct to allow these to be different from the decoded frame, and for simpler access.
* Added new mad_stream_options() and mad_decoder_options() API entries for special runtime decoding options.
* Added new MAD_OPTION_IGNORECRC and MAD_OPTION_HALFSAMPLERATE options.
* Added new MAD_FLAG_FREEFORMAT indicator flag.
* Fixed some bugs in the async decoder.
* Added a new mad_timer_multiply() API routine.
* Eliminated `+' from asm constraints under Intel for better compatibility with some compilers.
* Fixed a PIC-related problem in imdct_l_arm.S.
* Eliminated a static variable to make libmad thread-safe.
Version 0.12.5 (beta)
* Modified Layer III requantization to occur during Huffman decoding for significant performance gains.
* Optimized short block IMDCT by eliminating redundant calculations.
* Made several other Layer III performance improvements; added ASO_INTERLEAVE1, ASO_INTERLEAVE2, and ASO_ZEROCHECK architecture-specific options for best performance on various architectures.
* Optimized synthesis DCT to store result values as soon as they are calculated.
Version 0.12.4 (beta)
* New PowerPC fixed-point assembly courtesy of David Blythe.
* Reorganized fixed-point assembly routines for easier maintenance and better performance.
* Improved performance of subband synthesis through better indexing and fewer local variables.
* Added alias reduction for the lower two subbands of mixed short blocks, per a report of ambiguity with ISO/IEC 11172-3 and for uniformity with most other implementations. Also improved alias reduction performance using multiply/accumulate.
* Added --enable-strict-iso option to `configure' to override best accepted practices such as the alias reduction for mixed short blocks.
* Improved performance of Layer III IMDCT by using longer multiply/accumulate runs where possible.
Version 0.12.3 (beta)
* Added MPEG 2.5 support.
* Added preliminary support for parameterizing the binary point position in the fixed-point representation.
* Added multiply/accumulate optimization to the Layer III IMDCT for long blocks.
* Fixed a bug in the handling of Layer III mixed_block_flag.
* Fixed a configure problem when multiple -O CFLAGS are present.
Version 0.12.2 (beta)
* Rearranged the synthesis polyphase filterbank memory vector for better locality of reference, and rewrote mad_synth_frame() to accommodate, resulting in improved performance.
* Discovered a combination of compiler optimization flags that further improve performance.
* Changed some array references in layer3.c to pointer derefs.
Version 0.12.1 (beta)
* Resolved the intensity + MS joint stereo issue (a simple bug). OPT_ISKLUGE is no longer considered to be a kluge.
* Fixed another, hopefully last main_data memory bug.
* Split part of struct mad_frame into struct mad_header for convenience and size.
Version 0.12.0 (alpha)
* Changed the build environment to use automake and libtool. A libmad shared library can now be built using the --enable-shared option to `configure'.
* Added another callback to MAD's high-level decoder API after the frame header has been read but before the frame's audio data is decoded.
* Streamlined header processing so that mad_frame_decode() can be called with or without having already called mad_frame_header().
* Fixed some other header reading miscellany, including CRC handling and free bitrate detection, and frame length verification with free bitrates.
* Fixed a problem with Layer III free bitrates > 320 kbps. The main_data buffer size should now be large enough to handle any size frame, by virtue of the maximum possible part2_3_length.
* Further developed the async API; arbitrary messages can now be passed to the subsidiary decoding process.
* Streamlined timer.c and extended its interface. It now has support for video frame/field lengths, including output support for drop-frame encoding.
* Replaced many constant integer preprocessor defines with enums.
Version 0.11.4 (beta)
* Fixed free format bitrate discovery.
* Changed the timer implementation and extended its interface.
* Integrated Nicolas Pitre's patch for pre-shifting at compile-time and for better multiply/accumulate code output.
* Applied Simon Burge's patch to imdct_l_arm.S for a.out compatibility.
* Added -mtune=strongarm for all ARM targets.
Version 0.11.3 (beta)
* Added new --enable-speed and --enable-accuracy options for `configure' to automatically select appropriate SSO/ASO options, et al.
* Modified subband synthesis to use multiply/accumulate optimization (if available) for better speed and/or accuracy.
* Incorporated Andre McCurdy's changes for further rounding optimizations in the rest of his code.
Version 0.11.2 (beta)
* Incorporated Nicolas Pitre's ARM assembly and parameterized scaling changes.
* Incorporated Andre McCurdy's ARM assembly optimization (used only if --enable-aso is given to `configure' to enable architecture-specific optimizations.)
* Reduced FPM_INTEL assembly to two instructions.
* Fixed accuracy problems with certain FPM modes in synth.c.
* Improved the accuracy of FPM_APPROX.
* Improved the accuracy of SSO.
* Improved sync discovery by checking for a sync word in the following frame.
* Minor code clean-up.
* Added experimental rules for generating a libmad.so shared library.
Version 0.11.1 (beta)
* Moved libmad code into a separate directory.
* Changed SSO to be disabled by default, as output accuracy is deemed to be more important than speed in the general case.
* Fixed a bug in Layer III sanity checking that could cause a crash on certain random data input.
* Extended the Layer III requantization table from 8191 to 8206 as some encoders are known to use these values, even though ISO/IEC 11172-3 suggests the maximum should be 8191.
Version 0.11.0 (beta)
* Implemented MPEG-2 extension to Lower Sampling Frequencies.
* Improved Layer III performance by avoiding IMDCT calculation when all input samples are zero.
* Significantly reduced size of Layer II tables.
Version 0.10.3 (beta)
* Improved SSO output quality.
* Made portable to cygwin.
* Localized memory references in III_huffdecode() for better performance.
Version 0.10.2 (beta)
* Rewrote Layer III long block 36-point IMDCT routine for better performance.
* Improved subband synthesis fixed-point games somewhat.
Version 0.10.1 (beta)
* Added a subband synthesis optimization (SSO) which involves modifying the fixed-point multiplication method during windowing. This produces subtle differences in the output but improves performance greatly.
* Added I_STEREO and MS_STEREO flags to frame struct.
* Eliminated privately-used CRCFAILED flag.
* Fixed a bug where Layer III decoding could crash on some badly-formatted (e.g. non-MPEG) bitstreams.
* Miscellaneous code clean-up.
Version 0.10.0 (beta)
* Added SPARC fixed-point math support.
* Revamped libmad API for better high- and low-level support.
* Documented more of the code.
* Changed sync semantics such that new stream buffers are assumed to be sync-aligned.
* Changed Layer III to dynamically allocate static memory so as not to waste it (about 6.4K) when only decoding Layer I or Layer II.
===============================================================================
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