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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>
110 lines
5.8 KiB
C
110 lines
5.8 KiB
C
/*
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* MPEG-4 Audio common header
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* Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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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_MPEG4AUDIO_H
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#define AVCODEC_MPEG4AUDIO_H
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#include <stdint.h>
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#include "get_bits.h"
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#include "put_bits.h"
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typedef struct MPEG4AudioConfig {
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int object_type;
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int sampling_index;
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int sample_rate;
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int chan_config;
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int sbr; ///< -1 implicit, 1 presence
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int ext_object_type;
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int ext_sampling_index;
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int ext_sample_rate;
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int ext_chan_config;
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int channels;
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int ps; ///< -1 implicit, 1 presence
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} MPEG4AudioConfig;
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extern av_export const int avpriv_mpeg4audio_sample_rates[16];
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extern const uint8_t ff_mpeg4audio_channels[8];
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/**
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* Parse MPEG-4 systems extradata to retrieve audio configuration.
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* @param[in] c MPEG4AudioConfig structure to fill.
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* @param[in] buf Extradata from container.
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* @param[in] bit_size Extradata size in bits.
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* @param[in] sync_extension look for a sync extension after config if true.
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* @return On error -1 is returned, on success AudioSpecificConfig bit index in extradata.
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*/
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int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
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int bit_size, int sync_extension);
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enum AudioObjectType {
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AOT_NULL,
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// Support? Name
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AOT_AAC_MAIN, ///< Y Main
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AOT_AAC_LC, ///< Y Low Complexity
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AOT_AAC_SSR, ///< N (code in SoC repo) Scalable Sample Rate
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AOT_AAC_LTP, ///< Y Long Term Prediction
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AOT_SBR, ///< Y Spectral Band Replication
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AOT_AAC_SCALABLE, ///< N Scalable
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AOT_TWINVQ, ///< N Twin Vector Quantizer
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AOT_CELP, ///< N Code Excited Linear Prediction
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AOT_HVXC, ///< N Harmonic Vector eXcitation Coding
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AOT_TTSI = 12, ///< N Text-To-Speech Interface
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AOT_MAINSYNTH, ///< N Main Synthesis
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AOT_WAVESYNTH, ///< N Wavetable Synthesis
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AOT_MIDI, ///< N General MIDI
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AOT_SAFX, ///< N Algorithmic Synthesis and Audio Effects
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AOT_ER_AAC_LC, ///< N Error Resilient Low Complexity
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AOT_ER_AAC_LTP = 19, ///< N Error Resilient Long Term Prediction
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AOT_ER_AAC_SCALABLE, ///< N Error Resilient Scalable
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AOT_ER_TWINVQ, ///< N Error Resilient Twin Vector Quantizer
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AOT_ER_BSAC, ///< N Error Resilient Bit-Sliced Arithmetic Coding
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AOT_ER_AAC_LD, ///< N Error Resilient Low Delay
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AOT_ER_CELP, ///< N Error Resilient Code Excited Linear Prediction
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AOT_ER_HVXC, ///< N Error Resilient Harmonic Vector eXcitation Coding
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AOT_ER_HILN, ///< N Error Resilient Harmonic and Individual Lines plus Noise
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AOT_ER_PARAM, ///< N Error Resilient Parametric
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AOT_SSC, ///< N SinuSoidal Coding
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AOT_PS, ///< N Parametric Stereo
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AOT_SURROUND, ///< N MPEG Surround
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AOT_ESCAPE, ///< Y Escape Value
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AOT_L1, ///< Y Layer 1
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AOT_L2, ///< Y Layer 2
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AOT_L3, ///< Y Layer 3
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AOT_DST, ///< N Direct Stream Transfer
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AOT_ALS, ///< Y Audio LosslesS
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AOT_SLS, ///< N Scalable LosslesS
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AOT_SLS_NON_CORE, ///< N Scalable LosslesS (non core)
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AOT_ER_AAC_ELD, ///< N Error Resilient Enhanced Low Delay
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AOT_SMR_SIMPLE, ///< N Symbolic Music Representation Simple
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AOT_SMR_MAIN, ///< N Symbolic Music Representation Main
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AOT_USAC_NOSBR, ///< N Unified Speech and Audio Coding (no SBR)
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AOT_SAOC, ///< N Spatial Audio Object Coding
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AOT_LD_SURROUND, ///< N Low Delay MPEG Surround
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AOT_USAC, ///< N Unified Speech and Audio Coding
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};
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#define MAX_PCE_SIZE 304 ///<Maximum size of a PCE including the 3-bit ID_PCE
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///<marker and the comment
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int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb);
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#endif /* AVCODEC_MPEG4AUDIO_H */
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