mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 15571 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
Diego Biurrun
16 years ago
parent
66e9aa7463
commit
d8d12c1594
6 changed files with 3 additions and 241 deletions
@ -1,227 +0,0 @@ |
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/*
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* A52 decoder using liba52 |
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* Copyright (c) 2001 Fabrice Bellard. |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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/**
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* @file a52dec.c |
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* A52 decoder using liba52 |
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*/ |
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#include "avcodec.h" |
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#include <a52dec/a52.h> |
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#ifdef CONFIG_LIBA52BIN |
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#include <dlfcn.h> |
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static const char* const liba52name = "liba52.so.0"; |
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#endif |
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/**
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* liba52 - Copyright (C) Aaron Holtzman |
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* released under the GPL license. |
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*/ |
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typedef struct AC3DecodeState { |
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int flags; |
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int channels; |
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a52_state_t* state; |
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sample_t* samples; |
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/*
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* virtual method table |
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* |
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* using this function table so the liba52 doesn't |
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* have to be really linked together with ffmpeg |
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* and might be linked in runtime - this allows binary |
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* distribution of ffmpeg library which doens't depend |
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* on liba52 library - but if user has it installed |
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* it will be used - user might install such library |
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* separately |
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*/ |
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void* handle; |
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a52_state_t* (*a52_init)(uint32_t mm_accel); |
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sample_t* (*a52_samples)(a52_state_t * state); |
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int (*a52_syncinfo)(uint8_t * buf, int * flags, |
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int * sample_rate, int * bit_rate); |
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int (*a52_frame)(a52_state_t * state, uint8_t * buf, int * flags, |
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sample_t * level, sample_t bias); |
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void (*a52_dynrng)(a52_state_t * state, |
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sample_t (* call) (sample_t, void *), void * data); |
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int (*a52_block)(a52_state_t * state); |
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void (*a52_free)(a52_state_t * state); |
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} AC3DecodeState; |
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#ifdef CONFIG_LIBA52BIN |
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static void* dlsymm(void* handle, const char* symbol) |
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{ |
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void* f = dlsym(handle, symbol); |
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if (!f) |
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av_log( NULL, AV_LOG_ERROR, "A52 Decoder - function '%s' can't be resolved\n", symbol); |
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return f; |
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} |
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#endif |
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static av_cold int a52_decode_init(AVCodecContext *avctx) |
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{ |
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AC3DecodeState *s = avctx->priv_data; |
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#ifdef CONFIG_LIBA52BIN |
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s->handle = dlopen(liba52name, RTLD_LAZY); |
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if (!s->handle) |
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{ |
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av_log( avctx, AV_LOG_ERROR, "A52 library %s could not be opened! \n%s\n", liba52name, dlerror()); |
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return -1; |
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} |
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s->a52_init = (a52_state_t* (*)(uint32_t)) dlsymm(s->handle, "a52_init"); |
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s->a52_samples = (sample_t* (*)(a52_state_t*)) dlsymm(s->handle, "a52_samples"); |
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s->a52_syncinfo = (int (*)(uint8_t*, int*, int*, int*)) dlsymm(s->handle, "a52_syncinfo"); |
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s->a52_frame = (int (*)(a52_state_t*, uint8_t*, int*, sample_t*, sample_t)) dlsymm(s->handle, "a52_frame"); |
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s->a52_block = (int (*)(a52_state_t*)) dlsymm(s->handle, "a52_block"); |
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s->a52_free = (void (*)(a52_state_t*)) dlsymm(s->handle, "a52_free"); |
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if (!s->a52_init || !s->a52_samples || !s->a52_syncinfo |
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|| !s->a52_frame || !s->a52_block || !s->a52_free) |
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{ |
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dlclose(s->handle); |
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return -1; |
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} |
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#else |
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s->handle = 0; |
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s->a52_init = a52_init; |
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s->a52_samples = a52_samples; |
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s->a52_syncinfo = a52_syncinfo; |
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s->a52_frame = a52_frame; |
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s->a52_block = a52_block; |
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s->a52_free = a52_free; |
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#endif |
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s->state = s->a52_init(0); /* later use CPU flags */ |
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s->samples = s->a52_samples(s->state); |
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/* allow downmixing to stereo or mono */ |
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if (avctx->channels > 0 && avctx->request_channels > 0 && |
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avctx->request_channels < avctx->channels && |
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avctx->request_channels <= 2) { |
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avctx->channels = avctx->request_channels; |
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} |
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avctx->sample_fmt = SAMPLE_FMT_S16; |
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return 0; |
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} |
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/**** the following function comes from a52dec */ |
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static inline void float_to_int (float * _f, int16_t * s16, int nchannels) |
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{ |
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int i, j, c; |
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int32_t * f = (int32_t *) _f; // XXX assumes IEEE float format
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j = 0; |
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nchannels *= 256; |
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for (i = 0; i < 256; i++) { |
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for (c = 0; c < nchannels; c += 256) |
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s16[j++] = av_clip_int16(f[i + c] - 0x43c00000); |
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} |
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} |
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/**** end */ |
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#define HEADER_SIZE 7 |
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static int a52_decode_frame(AVCodecContext *avctx, |
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void *data, int *data_size, |
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uint8_t *buf, int buf_size) |
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{ |
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AC3DecodeState *s = avctx->priv_data; |
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int flags, i, len; |
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int sample_rate, bit_rate; |
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short *out_samples = data; |
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float level; |
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static const int ac3_channels[8] = { |
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2, 1, 2, 3, 3, 4, 4, 5 |
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}; |
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*data_size= 0; |
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if (buf_size < HEADER_SIZE) { |
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av_log(avctx, AV_LOG_ERROR, "Error decoding frame, not enough bytes for header\n"); |
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return -1; |
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} |
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len = s->a52_syncinfo(buf, &s->flags, &sample_rate, &bit_rate); |
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if (len == 0) { |
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av_log(avctx, AV_LOG_ERROR, "Error decoding frame, no sync byte at begin\n"); |
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return -1; |
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} |
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if (buf_size < len) { |
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av_log(avctx, AV_LOG_ERROR, "Error decoding frame, not enough bytes\n"); |
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return -1; |
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} |
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/* update codec info */ |
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avctx->sample_rate = sample_rate; |
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s->channels = ac3_channels[s->flags & 7]; |
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if (s->flags & A52_LFE) |
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s->channels++; |
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if (avctx->request_channels > 0 && |
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avctx->request_channels <= 2 && |
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avctx->request_channels < s->channels) { |
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avctx->channels = avctx->request_channels; |
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} else { |
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avctx->channels = s->channels; |
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} |
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avctx->bit_rate = bit_rate; |
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flags = s->flags; |
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if (avctx->channels == 1) |
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flags = A52_MONO; |
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else if (avctx->channels == 2) |
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flags = A52_STEREO; |
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else |
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flags |= A52_ADJUST_LEVEL; |
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level = 1; |
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if (s->a52_frame(s->state, buf, &flags, &level, 384)) { |
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fail: |
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av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n"); |
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return -1; |
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} |
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for (i = 0; i < 6; i++) { |
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if (s->a52_block(s->state)) |
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goto fail; |
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float_to_int(s->samples, out_samples + i * 256 * avctx->channels, avctx->channels); |
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} |
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*data_size = 6 * avctx->channels * 256 * sizeof(int16_t); |
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return len; |
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} |
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static av_cold int a52_decode_end(AVCodecContext *avctx) |
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{ |
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AC3DecodeState *s = avctx->priv_data; |
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s->a52_free(s->state); |
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#ifdef CONFIG_LIBA52BIN |
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dlclose(s->handle); |
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#endif |
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return 0; |
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} |
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AVCodec liba52_decoder = { |
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"liba52", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_AC3, |
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sizeof(AC3DecodeState), |
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a52_decode_init, |
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NULL, |
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a52_decode_end, |
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a52_decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("liba52 ATSC A/52 / AC-3"), |
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}; |
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