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ffmpeg / libavcodec / pcm-mpeg.c @ 72415b2a

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/*
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 * LPCM codecs for PCM formats found in MPEG streams
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 * Copyright (c) 2009 Christian Schmidt
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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 libavcodec/pcm-mpeg.c
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 * PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)
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 */
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#include "avcodec.h"
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#include "bytestream.h"
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/*
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 * Channel Mapping according to
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 * Blu-ray Disc Read-Only Format Version 1
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 * Part 3: Audio Visual Basic Specifications
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 * mono     M1    X
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 * stereo   L     R
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 * 3/0      L     R    C    X
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 * 2/1      L     R    S    X
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 * 3/1      L     R    C    S
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 * 2/2      L     R    LS   RS
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 * 3/2      L     R    C    LS    RS    X
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 * 3/2+lfe  L     R    C    LS    RS    lfe
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 * 3/4      L     R    C    LS    Rls   Rrs  RS   X
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 * 3/4+lfe  L     R    C    LS    Rls   Rrs  RS   lfe
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 */
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/**
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 * Parse the header of a LPCM frame read from a MPEG-TS stream
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 * @param avctx the codec context
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 * @param header pointer to the first four bytes of the data packet
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 */
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static int pcm_bluray_parse_header(AVCodecContext *avctx,
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                                   const uint8_t *header)
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{
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    static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
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    static const uint32_t channel_layouts[16] = {
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        0, CH_LAYOUT_MONO, 0, CH_LAYOUT_STEREO, CH_LAYOUT_SURROUND,
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        CH_LAYOUT_2_1, CH_LAYOUT_4POINT0, CH_LAYOUT_2_2, CH_LAYOUT_5POINT0,
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        CH_LAYOUT_5POINT1, CH_LAYOUT_7POINT0, CH_LAYOUT_7POINT1, 0, 0, 0, 0
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    };
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    static const uint8_t channels[16] = {
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        0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
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    };
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    uint8_t channel_layout = header[2] >> 4;
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    if (avctx->debug & FF_DEBUG_PICT_INFO)
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        dprintf(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
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                header[0], header[1], header[2], header[3]);
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    /* get the sample depth and derive the sample format from it */
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    avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
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    if (!avctx->bits_per_coded_sample) {
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        av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (0)\n");
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        return -1;
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    }
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    avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? SAMPLE_FMT_S16 :
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                                                             SAMPLE_FMT_S32;
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    /* get the sample rate. Not all values are known or exist. */
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    switch (header[2] & 0x0f) {
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    case 1:
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        avctx->sample_rate = 48000;
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        break;
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    case 4:
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        avctx->sample_rate = 96000;
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        break;
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    case 5:
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        avctx->sample_rate = 192000;
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        break;
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    default:
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        avctx->sample_rate = 0;
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        av_log(avctx, AV_LOG_ERROR, "unsupported sample rate (%d)\n",
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               header[2] & 0x0f);
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        return -1;
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    }
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    /*
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     * get the channel number (and mapping). Not all values are known or exist.
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     * It must be noted that the number of channels in the MPEG stream can
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     * differ from the actual meaningful number, e.g. mono audio still has two
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     * channels, one being empty.
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     */
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    avctx->channel_layout  = channel_layouts[channel_layout];
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    avctx->channels        =        channels[channel_layout];
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    if (!avctx->channels) {
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        av_log(avctx, AV_LOG_ERROR, "unsupported channel configuration (%d)\n",
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               channel_layout);
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        return -1;
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    }
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    avctx->bit_rate = avctx->channels * avctx->sample_rate *
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                      avctx->bits_per_coded_sample;
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    if (avctx->debug & FF_DEBUG_PICT_INFO)
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        dprintf(avctx,
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                "pcm_bluray_parse_header: %d channels, %d bits per sample, %d kHz, %d kbit\n",
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                avctx->channels, avctx->bits_per_coded_sample,
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                avctx->sample_rate, avctx->bit_rate);
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    return 0;
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}
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static int pcm_bluray_decode_frame(AVCodecContext *avctx,
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                                   void *data,
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                                   int *data_size,
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                                   AVPacket *avpkt)
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{
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    const uint8_t *src = avpkt->data;
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    int buf_size = avpkt->size;
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    int num_source_channels, channel, retval;
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    int sample_size, samples, output_size;
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    int16_t *dst16 = data;
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    int32_t *dst32 = data;
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    if (buf_size < 4) {
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        av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
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        return -1;
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    }
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    if (pcm_bluray_parse_header(avctx, src))
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        return -1;
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    src += 4;
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    buf_size -= 4;
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    /* There's always an even number of channels in the source */
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    num_source_channels = FFALIGN(avctx->channels, 2);
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    sample_size = (num_source_channels * avctx->bits_per_coded_sample) >> 3;
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    samples = buf_size / sample_size;
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    output_size = samples * avctx->channels *
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                  (avctx->sample_fmt == SAMPLE_FMT_S32 ? 4 : 2);
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    if (output_size > *data_size) {
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        av_log(avctx, AV_LOG_ERROR,
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               "Insufficient output buffer space (%d bytes, needed %d bytes)\n",
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               *data_size, output_size);
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        return -1;
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    }
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    *data_size = output_size;
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    if (samples) {
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        switch (avctx->channel_layout) {
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            /* cases with same number of source and coded channels */
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        case CH_LAYOUT_STEREO:
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        case CH_LAYOUT_4POINT0:
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        case CH_LAYOUT_2_2:
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            samples *= num_source_channels;
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            if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
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#if HAVE_BIGENDIAN
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                memcpy(dst16, src, output_size);
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#else
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                do {
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                    *dst16++ = bytestream_get_be16(&src);
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                } while (--samples);
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#endif
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            } else {
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                do {
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                    *dst32++ = bytestream_get_be24(&src) << 8;
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                } while (--samples);
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            }
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            break;
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        /* cases where number of source channels = coded channels + 1 */
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        case CH_LAYOUT_MONO:
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        case CH_LAYOUT_SURROUND:
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        case CH_LAYOUT_2_1:
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        case CH_LAYOUT_5POINT0:
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            if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
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                do {
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#if HAVE_BIGENDIAN
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                    memcpy(dst16, src, avctx->channels * 2);
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                    dst16 += avctx->channels;
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                    src += sample_size;
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#else
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                    channel = avctx->channels;
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                    do {
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                        *dst16++ = bytestream_get_be16(&src);
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                    } while (--channel);
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                    src += 2;
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#endif
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                } while (--samples);
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            } else {
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                do {
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                    channel = avctx->channels;
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                    do {
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                        *dst32++ = bytestream_get_be24(&src) << 8;
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                    } while (--channel);
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                    src += 3;
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                } while (--samples);
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            }
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            break;
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            /* remapping: L, R, C, LBack, RBack, LF */
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        case CH_LAYOUT_5POINT1:
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            if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
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                do {
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                    dst16[0] = bytestream_get_be16(&src);
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                    dst16[1] = bytestream_get_be16(&src);
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                    dst16[2] = bytestream_get_be16(&src);
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                    dst16[4] = bytestream_get_be16(&src);
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                    dst16[5] = bytestream_get_be16(&src);
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                    dst16[3] = bytestream_get_be16(&src);
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                    dst16 += 6;
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                } while (--samples);
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            } else {
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                do {
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                    dst32[0] = bytestream_get_be24(&src) << 8;
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                    dst32[1] = bytestream_get_be24(&src) << 8;
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                    dst32[2] = bytestream_get_be24(&src) << 8;
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                    dst32[4] = bytestream_get_be24(&src) << 8;
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                    dst32[5] = bytestream_get_be24(&src) << 8;
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                    dst32[3] = bytestream_get_be24(&src) << 8;
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                    dst32 += 6;
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                } while (--samples);
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            }
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            break;
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            /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
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        case CH_LAYOUT_7POINT0:
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            if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
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                do {
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                    dst16[0] = bytestream_get_be16(&src);
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                    dst16[1] = bytestream_get_be16(&src);
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                    dst16[2] = bytestream_get_be16(&src);
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                    dst16[5] = bytestream_get_be16(&src);
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                    dst16[3] = bytestream_get_be16(&src);
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                    dst16[4] = bytestream_get_be16(&src);
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                    dst16[6] = bytestream_get_be16(&src);
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                    dst16 += 7;
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                    src += 2;
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                } while (--samples);
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            } else {
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                do {
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                    dst32[0] = bytestream_get_be24(&src) << 8;
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                    dst32[1] = bytestream_get_be24(&src) << 8;
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                    dst32[2] = bytestream_get_be24(&src) << 8;
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                    dst32[5] = bytestream_get_be24(&src) << 8;
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                    dst32[3] = bytestream_get_be24(&src) << 8;
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                    dst32[4] = bytestream_get_be24(&src) << 8;
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                    dst32[6] = bytestream_get_be24(&src) << 8;
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                    dst32 += 7;
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                    src += 3;
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                } while (--samples);
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            }
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            break;
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            /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
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        case CH_LAYOUT_7POINT1:
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            if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
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                do {
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                    dst16[0] = bytestream_get_be16(&src);
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                    dst16[1] = bytestream_get_be16(&src);
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                    dst16[2] = bytestream_get_be16(&src);
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                    dst16[6] = bytestream_get_be16(&src);
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                    dst16[4] = bytestream_get_be16(&src);
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                    dst16[5] = bytestream_get_be16(&src);
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                    dst16[7] = bytestream_get_be16(&src);
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                    dst16[3] = bytestream_get_be16(&src);
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                    dst16 += 8;
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                } while (--samples);
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            } else {
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                do {
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                    dst32[0] = bytestream_get_be24(&src) << 8;
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                    dst32[1] = bytestream_get_be24(&src) << 8;
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                    dst32[2] = bytestream_get_be24(&src) << 8;
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                    dst32[6] = bytestream_get_be24(&src) << 8;
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                    dst32[4] = bytestream_get_be24(&src) << 8;
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                    dst32[5] = bytestream_get_be24(&src) << 8;
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                    dst32[7] = bytestream_get_be24(&src) << 8;
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                    dst32[3] = bytestream_get_be24(&src) << 8;
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                    dst32 += 8;
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                } while (--samples);
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            }
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            break;
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        }
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    }
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    retval = src - avpkt->data;
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    if (avctx->debug & FF_DEBUG_BITSTREAM)
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        dprintf(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
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                retval, *data_size);
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    return retval;
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}
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AVCodec pcm_bluray_decoder = {
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    "pcm_bluray",
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    AVMEDIA_TYPE_AUDIO,
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    CODEC_ID_PCM_BLURAY,
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    0,
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    NULL,
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    NULL,
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    NULL,
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    pcm_bluray_decode_frame,
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    .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16, SAMPLE_FMT_S32,
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                                         SAMPLE_FMT_NONE},
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    .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
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};