Remove unused libac3 AC3 decoding interface.

Originally committed as revision 7923 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3dec.c

-/*
- * AC3 decoder
- * Copyright (c) 2001 Fabrice Bellard.
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/**
- * @file ac3dec.c
- * AC3 decoder.
- */
-
-//#define DEBUG
-
-#include "avcodec.h"
-#include "libac3/ac3.h"
-
-/* currently, I use libac3 which is Copyright (C) Aaron Holtzman and
-   released under the GPL license. I may reimplement it someday... */
-typedef struct AC3DecodeState {
-    uint8_t inbuf[4096]; /* input buffer */
-    uint8_t *inbuf_ptr;
-    int frame_size;
-    int flags;
-    int channels;
-    ac3_state_t state;
-} AC3DecodeState;
-
-static int ac3_decode_init(AVCodecContext *avctx)
-{
-    AC3DecodeState *s = avctx->priv_data;
-
-    ac3_init ();
-    s->inbuf_ptr = s->inbuf;
-    s->frame_size = 0;
-    return 0;
-}
-
-stream_samples_t samples;
-
-/**** the following two functions comes from ac3dec */
-static inline int blah (int32_t i)
-{
-    if (i > 0x43c07fff)
-        return 32767;
-    else if (i < 0x43bf8000)
-        return -32768;
-    else
-        return i - 0x43c00000;
-}
-
-static inline void float_to_int (float * _f, int16_t * s16, int nchannels)
-{
-    int i, j, c;
-    int32_t * f = (int32_t *) _f;       // XXX assumes IEEE float format
-
-    j = 0;
-    nchannels *= 256;
-    for (i = 0; i < 256; i++) {
-        for (c = 0; c < nchannels; c += 256)
-            s16[j++] = blah (f[i + c]);
-    }
-}
-
-/**** end */
-
-#define HEADER_SIZE 7
-
-static int ac3_decode_frame(AVCodecContext *avctx,
-                            void *data, int *data_size,
-                            uint8_t *buf, int buf_size)
-{
-    AC3DecodeState *s = avctx->priv_data;
-    uint8_t *buf_ptr;
-    int flags, i, len;
-    int sample_rate, bit_rate;
-    short *out_samples = data;
-    float level;
-    static const int ac3_channels[8] = {
-        2, 1, 2, 3, 3, 4, 4, 5
-    };
-
-    buf_ptr = buf;
-    while (buf_size > 0) {
-        len = s->inbuf_ptr - s->inbuf;
-        if (s->frame_size == 0) {
-            /* no header seen : find one. We need at least 7 bytes to parse it */
-            len = HEADER_SIZE - len;
-            if (len > buf_size)
-                len = buf_size;
-            memcpy(s->inbuf_ptr, buf_ptr, len);
-            buf_ptr += len;
-            s->inbuf_ptr += len;
-            buf_size -= len;
-            if ((s->inbuf_ptr - s->inbuf) == HEADER_SIZE) {
-                len = ac3_syncinfo (s->inbuf, &s->flags, &sample_rate, &bit_rate);
-                if (len == 0) {
-                    /* no sync found : move by one byte (inefficient, but simple!) */
-                    memcpy(s->inbuf, s->inbuf + 1, HEADER_SIZE - 1);
-                    s->inbuf_ptr--;
-                } else {
-                    s->frame_size = len;
-                    /* update codec info */
-                    avctx->sample_rate = sample_rate;
-                    s->channels = ac3_channels[s->flags & 7];
-                    if (s->flags & AC3_LFE)
-                        s->channels++;
-                    if (avctx->channels == 0)
-                        /* No specific number of channel requested */
-                        avctx->channels = s->channels;
-                    else if (s->channels < avctx->channels) {
-                        av_log( avctx, AV_LOG_INFO, "ac3dec: AC3 Source channels are less than specified: output to %d channels.. (frmsize: %d)\n", s->channels, len);
-                        avctx->channels = s->channels;
-                    }
-                    avctx->bit_rate = bit_rate;
-                }
-            }
-        } else if (len < s->frame_size) {
-            len = s->frame_size - len;
-            if (len > buf_size)
-                len = buf_size;
-
-            memcpy(s->inbuf_ptr, buf_ptr, len);
-            buf_ptr += len;
-            s->inbuf_ptr += len;
-            buf_size -= len;
-        } else {
-            flags = s->flags;
-            if (avctx->channels == 1)
-                flags = AC3_MONO;
-            else if (avctx->channels == 2)
-                flags = AC3_STEREO;
-            else
-                flags |= AC3_ADJUST_LEVEL;
-            level = 1;
-            if (ac3_frame (&s->state, s->inbuf, &flags, &level, 384)) {
-            fail:
-                s->inbuf_ptr = s->inbuf;
-                s->frame_size = 0;
-                continue;
-            }
-            for (i = 0; i < 6; i++) {
-                if (ac3_block (&s->state))
-                    goto fail;
-                float_to_int (*samples, out_samples + i * 256 * avctx->channels, avctx->channels);
-            }
-            s->inbuf_ptr = s->inbuf;
-            s->frame_size = 0;
-            *data_size = 6 * avctx->channels * 256 * sizeof(int16_t);
-            break;
-        }
-    }
-    return buf_ptr - buf;
-}
-
-static int ac3_decode_end(AVCodecContext *s)
-{
-    return 0;
-}
-
-AVCodec ac3_decoder = {
-    "ac3",
-    CODEC_TYPE_AUDIO,
-    CODEC_ID_AC3,
-    sizeof(AC3DecodeState),
-    ac3_decode_init,
-    NULL,
-    ac3_decode_end,
-    ac3_decode_frame,
-};