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d66c52c2b3
This requires the makedef perl script by Derek, from the
c89-to-c99 repo. That scripts produces a .def file, listing
the symbols to be exported, based on the gcc version scripts
and the built object files.
To properly load non-function symbols from DLL files, the
data symbol declarations need to have the attribute
__declspec(dllimport) when building the calling code. (On mingw,
the linker can fix this up automatically, which is why it has not
been an issue so far. If this attribute is omitted, linking
actually succeeds, but reads from the table will not produce the
desired results at runtime.)
MSVC seems to manage to link DLLs (and run properly) even if
this attribute is present while building the library itself
(which normally isn't recommended) - other object files in the
same library manage to link to the symbol (with a small warning
at link time, like "warning LNK4049: locally defined symbol
_avpriv_mpa_bitrate_tab imported" - it doesn't seem to be possible
to squelch this warning), and the definition of the tables
themselves produce a warning that can be squelched ("warning C4273:
'avpriv_mpa_bitrate_tab' : inconsistent dll linkage, see previous
definition of 'avpriv_mpa_bitrate_tab').
In this setup, mingw isn't able to link object files that refer to
data symbols with __declspec(dllimport) without those symbols
actually being linked via a DLL (linking avcodec.dll ends up with
errors like "undefined reference to `__imp__avpriv_mpa_freq_tab'").
The dllimport declspec isn't needed at all in mingw, so we simply
choose not to declare it for other compilers than MSVC that requires
it. (If ICL support later requires it, the condition can be extended
later to include both of them.)
This also implies that code that is built to link to a certain
library as a DLL can't link to the same library as a static library.
Therefore, we only allow building either static or shared but not
both at the same time. (That is, static libraries as such can be,
and actually are, built - this is used for linking the test tools to
internal symbols in the libraries - but e.g. libavformat built to
link to libavcodec as a DLL cannot link statically to libavcodec.)
Also, linking to DLLs is slightly different from linking to shared
libraries on other platforms. DLLs use a thing called import
libraries, which is basically a stub library allowing the linker
to know which symbols exist in the DLL and what name the DLL will
have at runtime.
In mingw/gcc, the import library is usually named libfoo.dll.a,
which goes next to a static library named libfoo.a. This allows
gcc to pick the dynamic one, if available, from the normal -lfoo
switches, just as it does for libfoo.a vs libfoo.so on Unix. On
MSVC however, you need to literally specify the name of the import
library instead of the static library.
Signed-off-by: Martin Storsjö <martin@martin.st>
73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
/*
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* AC-3 tables
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_AC3TAB_H
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#define AVCODEC_AC3TAB_H
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#include "libavutil/common.h"
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#include "ac3.h"
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#if CONFIG_HARDCODED_TABLES
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# define HCONST const
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#else
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# define HCONST
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#endif
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extern const uint16_t ff_ac3_frame_size_tab[38][3];
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extern const uint8_t ff_ac3_channels_tab[8];
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extern av_export const uint16_t avpriv_ac3_channel_layout_tab[8];
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extern const uint8_t ff_ac3_enc_channel_map[8][2][6];
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extern const uint8_t ff_ac3_dec_channel_map[8][2][6];
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extern const uint16_t ff_ac3_sample_rate_tab[3];
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extern const uint16_t ff_ac3_bitrate_tab[19];
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extern const uint8_t ff_ac3_rematrix_band_tab[5];
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extern const uint8_t ff_eac3_default_cpl_band_struct[18];
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extern const int16_t ff_ac3_window[AC3_WINDOW_SIZE/2];
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extern const uint8_t ff_ac3_log_add_tab[260];
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extern const uint16_t ff_ac3_hearing_threshold_tab[AC3_CRITICAL_BANDS][3];
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extern const uint8_t ff_ac3_bap_tab[64];
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extern const uint8_t ff_ac3_slow_decay_tab[4];
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extern const uint8_t ff_ac3_fast_decay_tab[4];
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extern const uint16_t ff_ac3_slow_gain_tab[4];
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extern const uint16_t ff_ac3_db_per_bit_tab[4];
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extern const int16_t ff_ac3_floor_tab[8];
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extern const uint16_t ff_ac3_fast_gain_tab[8];
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extern const uint16_t ff_eac3_default_chmap[8];
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extern const uint8_t ff_ac3_band_start_tab[AC3_CRITICAL_BANDS+1];
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extern HCONST uint8_t ff_ac3_bin_to_band_tab[253];
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/** Custom channel map locations bitmask
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* Other channels described in documentation:
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* Lc/Rc pair, Lrs/Rrs pair, Ts, Lsd/Rsd pair,
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* Lw/Rw pair, Lvh/Rvh pair, Cvh, Reserved, LFE2
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*/
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enum CustomChannelMapLocation{
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AC3_CHMAP_L= 1<<(15-0),
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AC3_CHMAP_C= 1<<(15-1),
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AC3_CHMAP_R= 1<<(15-2),
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AC3_CHMAP_L_SUR= 1<<(15-3),
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AC3_CHMAP_R_SUR = 1<<(15-4),
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AC3_CHMAP_C_SUR= 1<<(15-7),
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AC3_CHMAP_LFE = 1<<(15-15)
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};
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#endif /* AVCODEC_AC3TAB_H */
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