dv.c 17.8 KB
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/*
 * General DV muxer/demuxer
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 * Copyright (c) 2003 Roman Shaposhnik
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 *
 * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
 * of DV technical info.
 *
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 * Raw DV format
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 * Copyright (c) 2002 Fabrice Bellard
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 *
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 * 50 Mbps (DVCPRO50) and 100 Mbps (DVCPRO HD) support
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 * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
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 * Funded by BBC Research & Development
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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
 * 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
 * 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
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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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#include <time.h>
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#include "avformat.h"
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#include "internal.h"
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#include "libavcodec/dv_profile.h"
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#include "libavcodec/dv.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/mathematics.h"
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#include "dv.h"

struct DVDemuxContext {
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    const DVprofile*  sys;    /* Current DV profile. E.g.: 525/60, 625/50 */
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    AVFormatContext*  fctx;
    AVStream*         vst;
    AVStream*         ast[4];
    AVPacket          audio_pkt[4];
    uint8_t           audio_buf[4][8192];
    int               ach;
    int               frames;
    uint64_t          abytes;
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};
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static inline uint16_t dv_audio_12to16(uint16_t sample)
{
    uint16_t shift, result;
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    sample = (sample < 0x800) ? sample : sample | 0xf000;
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    shift  = (sample & 0xf00) >> 8;
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    if (shift < 0x2 || shift > 0xd) {
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        result = sample;
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    } else if (shift < 0x8) {
        shift--;
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        result = (sample - (256 * shift)) << shift;
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    } else {
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        shift  = 0xe - shift;
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        result = ((sample + ((256 * shift) + 1)) << shift) - 1;
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    }

    return result;
}

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/*
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 * This is the dumbest implementation of all -- it simply looks at
 * a fixed offset and if pack isn't there -- fails. We might want
 * to have a fallback mechanism for complete search of missing packs.
 */
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static const uint8_t *dv_extract_pack(uint8_t *frame, enum dv_pack_type t)
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{
    int offs;
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    switch (t) {
    case dv_audio_source:
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        offs = (80 * 6 + 80 * 16 * 3 + 3);
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        break;
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    case dv_audio_control:
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        offs = (80 * 6 + 80 * 16 * 4 + 3);
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        break;
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    case dv_video_control:
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        offs = (80 * 5 + 48 + 5);
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        break;
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    default:
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        return NULL;
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    }
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    return frame[offs] == t ? &frame[offs] : NULL;
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}

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static const int dv_audio_frequency[3] = {
    48000, 44100, 32000,
};

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/*
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 * There's a couple of assumptions being made here:
 * 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
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 *    We can pass them upwards when libavcodec will be ready to deal with them.
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 * 2. We don't do software emphasis.
 * 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
 *    are converted into 16bit linear ones.
 */
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static int dv_extract_audio(uint8_t *frame, uint8_t **ppcm,
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                            const DVprofile *sys)
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{
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    int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
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    uint16_t lc, rc;
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    const uint8_t *as_pack;
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    uint8_t *pcm, ipcm;
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    as_pack = dv_extract_pack(frame, dv_audio_source);
    if (!as_pack)    /* No audio ? */
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        return 0;
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    smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
    freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
    quant = as_pack[4]      & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
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    if (quant > 1)
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        return -1;  /* unsupported quantization */
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    if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
        return AVERROR_INVALIDDATA;

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    size    = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
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    half_ch = sys->difseg_size / 2;
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    /* We work with 720p frames split in half, thus even frames have
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     * channels 0,1 and odd 2,3. */
    ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
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    /* for each DIF channel */
    for (chan = 0; chan < sys->n_difchan; chan++) {
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        /* next stereo channel (50Mbps and 100Mbps only) */
        pcm = ppcm[ipcm++];
        if (!pcm)
            break;

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        /* for each DIF segment */
        for (i = 0; i < sys->difseg_size; i++) {
            frame += 6 * 80; /* skip DIF segment header */
            if (quant == 1 && i == half_ch) {
                /* next stereo channel (12bit mode only) */
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                pcm = ppcm[ipcm++];
                if (!pcm)
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                    break;
            }
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            /* for each AV sequence */
            for (j = 0; j < 9; j++) {
                for (d = 8; d < 80; d += 2) {
                    if (quant == 0) {  /* 16bit quantization */
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                        of = sys->audio_shuffle[i][j] +
                             (d - 8) / 2 * sys->audio_stride;
                        if (of * 2 >= size)
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                            continue;

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                        /* FIXME: maybe we have to admit that DV is a
                         * big-endian PCM */
                        pcm[of * 2]     = frame[d + 1];
                        pcm[of * 2 + 1] = frame[d];

                        if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
                            pcm[of * 2 + 1] = 0;
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                    } else {           /* 12bit quantization */
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                        lc = ((uint16_t)frame[d]     << 4) |
                             ((uint16_t)frame[d + 2] >> 4);
                        rc = ((uint16_t)frame[d + 1] << 4) |
                             ((uint16_t)frame[d + 2] & 0x0f);
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                        lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
                        rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));

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                        of = sys->audio_shuffle[i % half_ch][j] +
                             (d - 8) / 3 * sys->audio_stride;
                        if (of * 2 >= size)
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                            continue;

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                        /* FIXME: maybe we have to admit that DV is a
                         * big-endian PCM */
                        pcm[of * 2]     = lc & 0xff;
                        pcm[of * 2 + 1] = lc >> 8;
                        of = sys->audio_shuffle[i % half_ch + half_ch][j] +
                             (d - 8) / 3 * sys->audio_stride;
                        /* FIXME: maybe we have to admit that DV is a
                         * big-endian PCM */
                        pcm[of * 2]     = rc & 0xff;
                        pcm[of * 2 + 1] = rc >> 8;
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                        ++d;
                    }
                }

                frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
            }
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        }
    }

    return size;
}

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static int dv_extract_audio_info(DVDemuxContext *c, uint8_t *frame)
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{
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    const uint8_t *as_pack;
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    int freq, stype, smpls, quant, i, ach;
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    as_pack = dv_extract_pack(frame, dv_audio_source);
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    if (!as_pack || !c->sys) {    /* No audio ? */
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        c->ach = 0;
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        return 0;
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    }
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    smpls = as_pack[1]      & 0x3f; /* samples in this frame - min. samples */
    freq  = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
    stype = as_pack[3]      & 0x1f; /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
    quant = as_pack[4]      & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
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    if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency)) {
        av_log(c->fctx, AV_LOG_ERROR,
               "Unrecognized audio sample rate index (%d)\n", freq);
        return 0;
    }

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    if (stype > 3) {
        av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
        c->ach = 0;
        return 0;
    }

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    /* note: ach counts PAIRS of channels (i.e. stereo channels) */
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    ach = ((int[4]) { 1, 0, 2, 4 })[stype];
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    if (ach == 1 && quant && freq == 2)
        ach = 2;
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    /* Dynamic handling of the audio streams in DV */
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    for (i = 0; i < ach; i++) {
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        if (!c->ast[i]) {
            c->ast[i] = avformat_new_stream(c->fctx, NULL);
            if (!c->ast[i])
                break;
            avpriv_set_pts_info(c->ast[i], 64, 1, 30000);
            c->ast[i]->codec->codec_type = AVMEDIA_TYPE_AUDIO;
            c->ast[i]->codec->codec_id   = AV_CODEC_ID_PCM_S16LE;

            av_init_packet(&c->audio_pkt[i]);
            c->audio_pkt[i].size         = 0;
            c->audio_pkt[i].data         = c->audio_buf[i];
            c->audio_pkt[i].stream_index = c->ast[i]->index;
            c->audio_pkt[i].flags       |= AV_PKT_FLAG_KEY;
        }
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        c->ast[i]->codec->sample_rate    = dv_audio_frequency[freq];
        c->ast[i]->codec->channels       = 2;
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        c->ast[i]->codec->channel_layout = AV_CH_LAYOUT_STEREO;
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        c->ast[i]->codec->bit_rate       = 2 * dv_audio_frequency[freq] * 16;
        c->ast[i]->start_time            = 0;
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    }
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    c->ach = i;
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    return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
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}

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static int dv_extract_video_info(DVDemuxContext *c, uint8_t *frame)
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{
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    const uint8_t *vsc_pack;
    AVCodecContext *avctx;
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    int apt, is16_9;
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    int size = 0;
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    if (c->sys) {
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        avctx = c->vst->codec;
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        avpriv_set_pts_info(c->vst, 64, c->sys->time_base.num,
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                            c->sys->time_base.den);
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        c->vst->avg_frame_rate = av_inv_q(c->vst->time_base);
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        if (!avctx->width) {
            avctx->width  = c->sys->width;
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            avctx->height = c->sys->height;
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        }
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        avctx->pix_fmt = c->sys->pix_fmt;
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        /* finding out SAR is a little bit messy */
        vsc_pack = dv_extract_pack(frame, dv_video_control);
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        apt      = frame[4] & 0x07;
        is16_9   = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
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                                 (!apt && (vsc_pack[2] & 0x07) == 0x07)));
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        c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
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        avctx->bit_rate = av_rescale_q(c->sys->frame_size,
                                       (AVRational) { 8, 1 },
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                                       c->sys->time_base);
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        size = c->sys->frame_size;
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    }
    return size;
}

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/* The following 3 functions constitute our interface to the world */
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DVDemuxContext *avpriv_dv_init_demux(AVFormatContext *s)
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{
    DVDemuxContext *c;

    c = av_mallocz(sizeof(DVDemuxContext));
    if (!c)
        return NULL;

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    c->vst = avformat_new_stream(s, NULL);
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    if (!c->vst) {
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        av_free(c);
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        return NULL;
    }
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    c->fctx                   = s;
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    c->vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
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    c->vst->codec->codec_id   = AV_CODEC_ID_DVVIDEO;
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    c->vst->codec->bit_rate   = 25000000;
    c->vst->start_time        = 0;
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    return c;
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}

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int avpriv_dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
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{
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    int size = -1;
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    int i;

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    for (i = 0; i < c->ach; i++) {
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        if (c->ast[i] && c->audio_pkt[i].size) {
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            *pkt                 = c->audio_pkt[i];
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            c->audio_pkt[i].size = 0;
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            size                 = pkt->size;
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            break;
        }
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    }
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    return size;
}

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int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
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                             uint8_t *buf, int buf_size)
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{
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    int size, i;
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    uint8_t *ppcm[5] = { 0 };
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    if (buf_size < DV_PROFILE_BYTES ||
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        !(c->sys = avpriv_dv_frame_profile(c->sys, buf, buf_size)) ||
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        buf_size < c->sys->frame_size) {
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        return -1;   /* Broken frame, or not enough data */
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    }
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    /* Queueing audio packet */
    /* FIXME: in case of no audio/bad audio we have to do something */
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    size = dv_extract_audio_info(c, buf);
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    for (i = 0; i < c->ach; i++) {
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        c->audio_pkt[i].size = size;
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        c->audio_pkt[i].pts  = c->abytes * 30000 * 8 /
                               c->ast[i]->codec->bit_rate;
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        ppcm[i] = c->audio_buf[i];
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    }
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    if (c->ach)
        dv_extract_audio(buf, ppcm, c->sys);
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    /* We work with 720p frames split in half, thus even frames have
     * channels 0,1 and odd 2,3. */
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    if (c->sys->height == 720) {
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        if (buf[1] & 0x0C) {
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            c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
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        } else {
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            c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
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            c->abytes           += size;
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        }
    } else {
        c->abytes += size;
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    }

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    /* Now it's time to return video packet */
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    size = dv_extract_video_info(c, buf);
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    av_init_packet(pkt);
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    pkt->data         = buf;
    pkt->size         = size;
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    pkt->flags       |= AV_PKT_FLAG_KEY;
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    pkt->stream_index = c->vst->index;
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    pkt->pts          = c->frames;
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    c->frames++;
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    return size;
}
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static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
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                               int64_t timestamp, int flags)
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{
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    // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
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    const DVprofile *sys = avpriv_dv_codec_profile(c->vst->codec);
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    int64_t offset;
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    int64_t size       = avio_size(s->pb) - s->data_offset;
    int64_t max_offset = ((size - 1) / sys->frame_size) * sys->frame_size;
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    offset = sys->frame_size * timestamp;
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    if (size >= 0 && offset > max_offset)
        offset = max_offset;
    else if (offset < 0)
        offset = 0;
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    return offset + s->data_offset;
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}

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void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
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{
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    c->frames = frame_offset;
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    if (c->ach)
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        c->abytes = av_rescale_q(c->frames, c->sys->time_base,
                                 (AVRational) { 8, c->ast[0]->codec->bit_rate });

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    c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
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    c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
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}

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/************************************************************
 * Implementation of the easiest DV storage of all -- raw DV.
 ************************************************************/
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typedef struct RawDVContext {
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    DVDemuxContext *dv_demux;
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    uint8_t         buf[DV_MAX_FRAME_SIZE];
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} RawDVContext;

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static int dv_read_header(AVFormatContext *s)
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{
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    unsigned state, marker_pos = 0;
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    RawDVContext *c = s->priv_data;
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    c->dv_demux = avpriv_dv_init_demux(s);
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    if (!c->dv_demux)
        return -1;
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    state = avio_rb32(s->pb);
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    while ((state & 0xffffff7f) != 0x1f07003f) {
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        if (s->pb->eof_reached) {
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            av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
            return -1;
        }
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        if (state == 0x003f0700 || state == 0xff3f0700)
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            marker_pos = avio_tell(s->pb);
        if (state == 0xff3f0701 && avio_tell(s->pb) - marker_pos == 80) {
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            avio_seek(s->pb, -163, SEEK_CUR);
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            state = avio_rb32(s->pb);
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            break;
        }
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        state = (state << 8) | avio_r8(s->pb);
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    }
    AV_WB32(c->buf, state);

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    if (avio_read(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) <= 0 ||
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        avio_seek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
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        return AVERROR(EIO);
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    c->dv_demux->sys = avpriv_dv_frame_profile(c->dv_demux->sys,
                                               c->buf,
                                               DV_PROFILE_BYTES);
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    if (!c->dv_demux->sys) {
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        av_log(s, AV_LOG_ERROR,
               "Can't determine profile of DV input stream.\n");
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        return -1;
    }

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    s->bit_rate = av_rescale_q(c->dv_demux->sys->frame_size,
                               (AVRational) { 8, 1 },
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                               c->dv_demux->sys->time_base);
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    return 0;
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}

static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int size;
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    RawDVContext *c = s->priv_data;

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    size = avpriv_dv_get_packet(c->dv_demux, pkt);
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    if (size < 0) {
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        if (!c->dv_demux->sys)
            return AVERROR(EIO);
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        size = c->dv_demux->sys->frame_size;
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        if (avio_read(s->pb, c->buf, size) <= 0)
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            return AVERROR(EIO);
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        size = avpriv_dv_produce_packet(c->dv_demux, pkt, c->buf, size);
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    }

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    return size;
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}

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static int dv_read_seek(AVFormatContext *s, int stream_index,
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                        int64_t timestamp, int flags)
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{
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    RawDVContext *r   = s->priv_data;
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    DVDemuxContext *c = r->dv_demux;
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    int64_t offset    = dv_frame_offset(s, c, timestamp, flags);
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    if (avio_seek(s->pb, offset, SEEK_SET) < 0)
        return -1;
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    ff_dv_offset_reset(c, offset / c->sys->frame_size);
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    return 0;
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}

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static int dv_read_close(AVFormatContext *s)
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{
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    RawDVContext *c = s->priv_data;
    av_free(c->dv_demux);
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    return 0;
}

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static int dv_probe(AVProbeData *p)
{
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    unsigned state, marker_pos = 0;
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    int i;
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    int matches           = 0;
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    int secondary_matches = 0;
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    if (p->buf_size < 5)
        return 0;

    state = AV_RB32(p->buf);
    for (i = 4; i < p->buf_size; i++) {
        if ((state & 0xffffff7f) == 0x1f07003f)
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            matches++;
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        // any section header, also with seq/chan num != 0,
        // should appear around every 12000 bytes, at least 10 per frame
        if ((state & 0xff07ff7f) == 0x1f07003f)
            secondary_matches++;
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        if (state == 0x003f0700 || state == 0xff3f0700)
            marker_pos = i;
        if (state == 0xff3f0701 && i - marker_pos == 80)
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            matches++;
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        state = (state << 8) | p->buf[i];
    }

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    if (matches && p->buf_size / matches < 1024 * 1024) {
        if (matches > 4 ||
            (secondary_matches >= 10 &&
             p->buf_size / secondary_matches < 24000))
            // not max to avoid dv in mov to match
            return AVPROBE_SCORE_MAX * 3 / 4;
        return AVPROBE_SCORE_MAX / 4;
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    }
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    return 0;
}

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#if CONFIG_DV_DEMUXER
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AVInputFormat ff_dv_demuxer = {
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    .name           = "dv",
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    .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
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    .priv_data_size = sizeof(RawDVContext),
    .read_probe     = dv_probe,
    .read_header    = dv_read_header,
    .read_packet    = dv_read_packet,
    .read_close     = dv_read_close,
    .read_seek      = dv_read_seek,
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    .extensions     = "dv,dif",
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};
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#endif