audio.c 17.5 KB
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/*****************************************************************************
 * audio.c: audio decoder using ffmpeg library
 *****************************************************************************
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 * Copyright (C) 1999-2003 the VideoLAN team
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 * $Id$
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 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
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 *          Gildas Bazin <gbazin@videolan.org>
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
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 *
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 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; 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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 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
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#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

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#include <vlc_common.h>
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#include <vlc_aout.h>
#include <vlc_codec.h>
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#include <vlc_avcodec.h>
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/* ffmpeg header */
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#ifdef HAVE_LIBAVCODEC_AVCODEC_H
#   include <libavcodec/avcodec.h>
#elif defined(HAVE_FFMPEG_AVCODEC_H)
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#   include <ffmpeg/avcodec.h>
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#else
#   include <avcodec.h>
#endif
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#include "avcodec.h"
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/*****************************************************************************
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 * decoder_sys_t : decoder descriptor
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 *****************************************************************************/
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struct decoder_sys_t
{
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    FFMPEG_COMMON_MEMBERS
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    /* Temporary buffer for libavcodec */
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    int     i_output_max;
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    uint8_t *p_output;

    /*
     * Output properties
     */
    audio_sample_format_t aout_format;
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    date_t                end_date;
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    /*
     *
     */
    uint8_t *p_samples;
    int     i_samples;
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    /* */
    int     i_reject_count;
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    /* */
    bool    b_extract;
    int     pi_extraction[AOUT_CHAN_MAX];
    int     i_previous_channels;
    int64_t i_previous_layout;
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};
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static void SetupOutputFormat( decoder_t *p_dec, bool b_trust );
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/*****************************************************************************
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 * InitAudioDec: initialize audio decoder
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 *****************************************************************************
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 * The ffmpeg codec will be opened, some memory allocated.
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 *****************************************************************************/
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int InitAudioDec( decoder_t *p_dec, AVCodecContext *p_context,
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                      AVCodec *p_codec, int i_codec_id, const char *psz_namecodec )
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{
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    decoder_sys_t *p_sys;
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    /* Allocate the memory needed to store the decoder's structure */
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    if( ( p_dec->p_sys = p_sys = malloc(sizeof(*p_sys)) ) == NULL )
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    {
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        return VLC_ENOMEM;
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    }

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    p_sys->p_context = p_context;
    p_sys->p_codec = p_codec;
    p_sys->i_codec_id = i_codec_id;
    p_sys->psz_namecodec = psz_namecodec;
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    p_sys->b_delayed_open = false;
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    /* ***** Fill p_context with init values ***** */
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    p_sys->p_context->sample_rate = p_dec->fmt_in.audio.i_rate;
    p_sys->p_context->channels = p_dec->fmt_in.audio.i_channels;
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    p_sys->p_context->block_align = p_dec->fmt_in.audio.i_blockalign;
    p_sys->p_context->bit_rate = p_dec->fmt_in.i_bitrate;
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#if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
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    p_sys->p_context->bits_per_sample = p_dec->fmt_in.audio.i_bitspersample;
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#else
    p_sys->p_context->bits_per_coded_sample = p_dec->fmt_in.audio.i_bitspersample;
#endif
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    if( p_dec->fmt_in.i_extra > 0 )
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    {
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        const uint8_t * const p_src = p_dec->fmt_in.p_extra;
        int i_offset;
        int i_size;
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        if( p_dec->fmt_in.i_codec == VLC_CODEC_FLAC )
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        {
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            i_offset = 8;
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            i_size = p_dec->fmt_in.i_extra - 8;
        }
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        else if( p_dec->fmt_in.i_codec == VLC_CODEC_ALAC )
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        {
            static const uint8_t p_pattern[] = { 0, 0, 0, 36, 'a', 'l', 'a', 'c' };
            /* Find alac atom XXX it is a bit ugly */
            for( i_offset = 0; i_offset < p_dec->fmt_in.i_extra - sizeof(p_pattern); i_offset++ )
            {
                if( !memcmp( &p_src[i_offset], p_pattern, sizeof(p_pattern) ) )
                    break;
            }
            i_size = __MIN( p_dec->fmt_in.i_extra - i_offset, 36 );
            if( i_size < 36 )
                i_size = 0;
        }
        else
        {
            i_offset = 0;
            i_size = p_dec->fmt_in.i_extra;
        }
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        if( i_size > 0 )
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        {
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            p_sys->p_context->extradata =
                malloc( i_size + FF_INPUT_BUFFER_PADDING_SIZE );
            if( p_sys->p_context->extradata )
            {
                uint8_t *p_dst = p_sys->p_context->extradata;

                p_sys->p_context->extradata_size = i_size;

                memcpy( &p_dst[0],            &p_src[i_offset], i_size );
                memset( &p_dst[i_size], 0, FF_INPUT_BUFFER_PADDING_SIZE );
            }
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        }
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    }
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    else
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    {
        p_sys->p_context->extradata_size = 0;
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        p_sys->p_context->extradata = NULL;
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    }
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    /* ***** Open the codec ***** */
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    int ret;
    vlc_avcodec_lock();
    ret = avcodec_open( p_sys->p_context, p_sys->p_codec );
    vlc_avcodec_unlock();
    if( ret < 0 )
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    {
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        msg_Err( p_dec, "cannot open codec (%s)", p_sys->psz_namecodec );
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        free( p_sys->p_context->extradata );
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        free( p_sys );
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        return VLC_EGENERIC;
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    }
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    msg_Dbg( p_dec, "ffmpeg codec (%s) started", p_sys->psz_namecodec );
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    switch( i_codec_id )
    {
    case CODEC_ID_WAVPACK:
        p_sys->i_output_max = 8 * sizeof(int32_t) * 131072;
        break;
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    case CODEC_ID_TTA:
        p_sys->i_output_max = p_sys->p_context->channels * sizeof(int32_t) * p_sys->p_context->sample_rate * 2;
        break;
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    case CODEC_ID_FLAC:
        p_sys->i_output_max = 8 * sizeof(int32_t) * 65535;
        break;
    default:
        p_sys->i_output_max = 0;
        break;
    }
    if( p_sys->i_output_max < AVCODEC_MAX_AUDIO_FRAME_SIZE )
        p_sys->i_output_max = AVCODEC_MAX_AUDIO_FRAME_SIZE;
    msg_Dbg( p_dec, "Using %d bytes output buffer", p_sys->i_output_max );
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    p_sys->p_output = av_malloc( p_sys->i_output_max );
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    p_sys->p_samples = NULL;
    p_sys->i_samples = 0;
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    p_sys->i_reject_count = 0;
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    p_sys->b_extract = false;
    p_sys->i_previous_channels = 0;
    p_sys->i_previous_layout = 0;
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    date_Set( &p_sys->end_date, 0 );
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    if( p_dec->fmt_in.audio.i_rate )
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        date_Init( &p_sys->end_date, p_dec->fmt_in.audio.i_rate, 1 );
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    /* */
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    p_dec->fmt_out.i_cat = AUDIO_ES;
    /* Try to set as much informations as possible but do not trust it */
    SetupOutputFormat( p_dec, false );
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    return VLC_SUCCESS;
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}

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/*****************************************************************************
 * SplitBuffer: Needed because aout really doesn't like big audio chunk and
 * wma produces easily > 30000 samples...
 *****************************************************************************/
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static aout_buffer_t *SplitBuffer( decoder_t *p_dec )
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{
    decoder_sys_t *p_sys = p_dec->p_sys;
    int i_samples = __MIN( p_sys->i_samples, 4096 );
    aout_buffer_t *p_buffer;

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    if( i_samples == 0 ) return NULL;

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    if( ( p_buffer = decoder_NewAudioBuffer( p_dec, i_samples ) ) == NULL )
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        return NULL;

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    p_buffer->start_date = date_Get( &p_sys->end_date );
    p_buffer->end_date = date_Increment( &p_sys->end_date, i_samples );
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    if( p_sys->b_extract )
        aout_ChannelExtract( p_buffer->p_buffer, p_dec->fmt_out.audio.i_channels,
                             p_sys->p_samples, p_sys->p_context->channels, i_samples,
                             p_sys->pi_extraction, p_dec->fmt_out.audio.i_bitspersample );
    else
        memcpy( p_buffer->p_buffer, p_sys->p_samples, p_buffer->i_nb_bytes );
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    p_sys->p_samples += i_samples * p_sys->p_context->channels * ( p_dec->fmt_out.audio.i_bitspersample / 8 );
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    p_sys->i_samples -= i_samples;

    return p_buffer;
}

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/*****************************************************************************
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 * DecodeAudio: Called to decode one frame
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 *****************************************************************************/
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aout_buffer_t * DecodeAudio ( decoder_t *p_dec, block_t **pp_block )
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{
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    decoder_sys_t *p_sys = p_dec->p_sys;
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    int i_used, i_output;
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    aout_buffer_t *p_buffer;
    block_t *p_block;

    if( !pp_block || !*pp_block ) return NULL;
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    p_block = *pp_block;
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    if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
    {
        block_Release( p_block );
        avcodec_flush_buffers( p_sys->p_context );
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        p_sys->i_samples = 0;
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        date_Set( &p_sys->end_date, 0 );
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        if( p_sys->i_codec_id == CODEC_ID_MP2 || p_sys->i_codec_id == CODEC_ID_MP3 )
            p_sys->i_reject_count = 3;
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        return NULL;
    }

    if( p_sys->i_samples > 0 )
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    {
        /* More data */
        p_buffer = SplitBuffer( p_dec );
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        if( !p_buffer ) block_Release( p_block );
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        return p_buffer;
    }

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    if( !date_Get( &p_sys->end_date ) && !p_block->i_pts )
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    {
        /* We've just started the stream, wait for the first PTS. */
        block_Release( p_block );
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        return NULL;
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    }
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    if( p_block->i_buffer <= 0 )
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    {
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        block_Release( p_block );
        return NULL;
    }
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    i_output = __MAX( p_block->i_buffer, p_sys->i_output_max );
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    if( i_output > p_sys->i_output_max )
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    {
        /* Grow output buffer if necessary (eg. for PCM data) */
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        p_sys->p_output = av_realloc( p_sys->p_output, i_output );
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    }

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    *pp_block = p_block = block_Realloc( p_block, 0, p_block->i_buffer + FF_INPUT_BUFFER_PADDING_SIZE );
    if( !p_block )
        return NULL;
    p_block->i_buffer -= FF_INPUT_BUFFER_PADDING_SIZE;
    memset( &p_block->p_buffer[p_block->i_buffer], 0, FF_INPUT_BUFFER_PADDING_SIZE );

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#if LIBAVCODEC_VERSION_INT >= ((52<<16)+(0<<8)+0)
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    i_used = avcodec_decode_audio2( p_sys->p_context,
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                                   (int16_t*)p_sys->p_output, &i_output,
                                   p_block->p_buffer, p_block->i_buffer );
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#else
    i_used = avcodec_decode_audio( p_sys->p_context,
                                   (int16_t*)p_sys->p_output, &i_output,
                                   p_block->p_buffer, p_block->i_buffer );
#endif
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    if( i_used < 0 || i_output < 0 )
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    {
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        if( i_used < 0 )
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            msg_Warn( p_dec, "cannot decode one frame (%zu bytes)",
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                      p_block->i_buffer );

        block_Release( p_block );
        return NULL;
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    }
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    else if( (size_t)i_used > p_block->i_buffer )
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    {
        i_used = p_block->i_buffer;
    }
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    p_block->i_buffer -= i_used;
    p_block->p_buffer += i_used;

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    if( p_sys->p_context->channels <= 0 || p_sys->p_context->channels > 8 ||
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        p_sys->p_context->sample_rate <= 0 )
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    {
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        msg_Warn( p_dec, "invalid audio properties channels count %d, sample rate %d",
                  p_sys->p_context->channels, p_sys->p_context->sample_rate );
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        block_Release( p_block );
        return NULL;
    }

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    if( p_dec->fmt_out.audio.i_rate != (unsigned int)p_sys->p_context->sample_rate )
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    {
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        date_Init( &p_sys->end_date, p_sys->p_context->sample_rate, 1 );
        date_Set( &p_sys->end_date, p_block->i_pts );
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    }

    /* **** Set audio output parameters **** */
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    SetupOutputFormat( p_dec, true );
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    if( p_block->i_pts != 0 &&
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        p_block->i_pts != date_Get( &p_sys->end_date ) )
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    {
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        date_Set( &p_sys->end_date, p_block->i_pts );
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    }
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    p_block->i_pts = 0;
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    /* **** Now we can output these samples **** */
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    p_sys->i_samples = i_output / (p_dec->fmt_out.audio.i_bitspersample / 8) / p_sys->p_context->channels;
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    p_sys->p_samples = p_sys->p_output;
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    /* Silent unwanted samples */
    if( p_sys->i_reject_count > 0 )
    {
        memset( p_sys->p_output, 0, i_output );
        p_sys->i_reject_count--;
    }

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    p_buffer = SplitBuffer( p_dec );
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    if( !p_buffer ) block_Release( p_block );
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    return p_buffer;
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}

/*****************************************************************************
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 * EndAudioDec: audio decoder destruction
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 *****************************************************************************/
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void EndAudioDec( decoder_t *p_dec )
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{
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    decoder_sys_t *p_sys = p_dec->p_sys;

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    av_free( p_sys->p_output );
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}
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/*****************************************************************************
 *
 *****************************************************************************/
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#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT( 52, 2, 0 )
#   define LIBAVCODEC_AUDIO_LAYOUT
#else
#   warning "Audio channel layout is unsupported by your avcodec version."
#endif

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#if defined(LIBAVCODEC_AUDIO_LAYOUT)
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static const uint64_t pi_channels_map[][2] =
{
    { CH_FRONT_LEFT,        AOUT_CHAN_LEFT },
    { CH_FRONT_RIGHT,       AOUT_CHAN_RIGHT },
    { CH_FRONT_CENTER,      AOUT_CHAN_CENTER },
    { CH_LOW_FREQUENCY,     AOUT_CHAN_LFE },
    { CH_BACK_LEFT,         AOUT_CHAN_REARLEFT },
    { CH_BACK_RIGHT,        AOUT_CHAN_REARRIGHT },
    { CH_FRONT_LEFT_OF_CENTER, 0 },
    { CH_FRONT_RIGHT_OF_CENTER, 0 },
    { CH_BACK_CENTER,       AOUT_CHAN_REARCENTER },
    { CH_SIDE_LEFT,         AOUT_CHAN_MIDDLELEFT },
    { CH_SIDE_RIGHT,        AOUT_CHAN_MIDDLERIGHT },
    { CH_TOP_CENTER,        0 },
    { CH_TOP_FRONT_LEFT,    0 },
    { CH_TOP_FRONT_CENTER,  0 },
    { CH_TOP_FRONT_RIGHT,   0 },
    { CH_TOP_BACK_LEFT,     0 },
    { CH_TOP_BACK_CENTER,   0 },
    { CH_TOP_BACK_RIGHT,    0 },
    { CH_STEREO_LEFT,       0 },
    { CH_STEREO_RIGHT,      0 },
};
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#else
static const uint64_t pi_channels_map[][2] =
{
    { 0, AOUT_CHAN_LEFT },
    { 0, AOUT_CHAN_RIGHT },
    { 0, AOUT_CHAN_CENTER },
    { 0, AOUT_CHAN_LFE },
    { 0, AOUT_CHAN_REARLEFT },
    { 0, AOUT_CHAN_REARRIGHT },
    { 0, 0 },
    { 0, 0 },
    { 0, AOUT_CHAN_REARCENTER },
    { 0, AOUT_CHAN_MIDDLELEFT },
    { 0, AOUT_CHAN_MIDDLERIGHT },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
    { 0, 0 },
};
#endif
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static void SetupOutputFormat( decoder_t *p_dec, bool b_trust )
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{
    decoder_sys_t *p_sys = p_dec->p_sys;

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#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT( 51, 65, 0 )
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    switch( p_sys->p_context->sample_fmt )
    {
    case SAMPLE_FMT_U8:
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        p_dec->fmt_out.i_codec = VLC_CODEC_U8;
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        p_dec->fmt_out.audio.i_bitspersample = 8;
        break;
    case SAMPLE_FMT_S32:
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        p_dec->fmt_out.i_codec = VLC_CODEC_S32N;
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        p_dec->fmt_out.audio.i_bitspersample = 32;
        break;
    case SAMPLE_FMT_FLT:
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        p_dec->fmt_out.i_codec = VLC_CODEC_FL32;
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        p_dec->fmt_out.audio.i_bitspersample = 32;
        break;
    case SAMPLE_FMT_DBL:
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        p_dec->fmt_out.i_codec = VLC_CODEC_FL64;
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        p_dec->fmt_out.audio.i_bitspersample = 64;
        break;

    case SAMPLE_FMT_S16:
    default:
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        p_dec->fmt_out.i_codec = VLC_CODEC_S16N;
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        p_dec->fmt_out.audio.i_bitspersample = 16;
        break;
    }
#else
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    p_dec->fmt_out.i_codec = VLC_CODEC_S16N;
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    p_dec->fmt_out.audio.i_bitspersample = 16;
#endif
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    p_dec->fmt_out.audio.i_rate     = p_sys->p_context->sample_rate;

    /* */
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#if defined(LIBAVCODEC_AUDIO_LAYOUT)
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    if( p_sys->i_previous_channels == p_sys->p_context->channels &&
        p_sys->i_previous_layout == p_sys->p_context->channel_layout )
        return;
#else
    if( p_sys->i_previous_channels == p_sys->p_context->channels )
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        return;
#endif
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    if( b_trust )
    {
        p_sys->i_previous_channels = p_sys->p_context->channels;
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#if defined(LIBAVCODEC_AUDIO_LAYOUT)
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        p_sys->i_previous_layout = p_sys->p_context->channel_layout;
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#endif
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    }
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    /* Specified order
     * FIXME should we use fmt_in.audio.i_physical_channels or not ?
     */
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#if defined(LIBAVCODEC_AUDIO_LAYOUT)
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    const unsigned i_order_max = 8 * sizeof(p_sys->p_context->channel_layout);
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#else
    const unsigned i_order_max = 64;
#endif
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    uint32_t pi_order_src[i_order_max];
    int i_channels_src = 0;

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#if defined(LIBAVCODEC_AUDIO_LAYOUT)
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    if( p_sys->p_context->channel_layout )
    {
        for( unsigned i = 0; i < sizeof(pi_channels_map)/sizeof(*pi_channels_map); i++ )
        {
            if( p_sys->p_context->channel_layout & pi_channels_map[i][0] )
                pi_order_src[i_channels_src++] = pi_channels_map[i][1];
        }
    }
    else
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#endif
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    {
        /* Create default order  */
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        if( b_trust )
            msg_Warn( p_dec, "Physical channel configuration not set : guessing" );
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        for( unsigned int i = 0; i < __MIN( i_order_max, (unsigned)p_sys->p_context->channels ); i++ )
        {
            if( i < sizeof(pi_channels_map)/sizeof(*pi_channels_map) )
                pi_order_src[i_channels_src++] = pi_channels_map[i][1];
        }
    }
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    if( i_channels_src != p_sys->p_context->channels && b_trust )
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        msg_Err( p_dec, "Channel layout not understood" );

    uint32_t i_layout_dst;
    int      i_channels_dst;
    p_sys->b_extract = aout_CheckChannelExtraction( p_sys->pi_extraction,
                                                    &i_layout_dst, &i_channels_dst,
                                                    NULL, pi_order_src, i_channels_src );
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    if( i_channels_dst != i_channels_src && b_trust )
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        msg_Warn( p_dec, "%d channels are dropped", i_channels_src - i_channels_dst );

    p_dec->fmt_out.audio.i_physical_channels =
    p_dec->fmt_out.audio.i_original_channels = i_layout_dst;
    p_dec->fmt_out.audio.i_channels = i_channels_dst;
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}
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