dvenc.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * General DV muxer/demuxer
 * Copyright (c) 2003 Roman Shaposhnik
 *
 * Many thanks to Dan Dennedy <[e-mail]> for providing wealth
 * of DV technical info.
 *
 * Raw DV format
 * Copyright (c) 2002 Fabrice Bellard.
 *
 * 50 Mbps (DVCPRO50) support
 * Copyright (c) 2006 Daniel Maas <[e-mail]>
 *
 * 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
 */
#include <time.h>
#include <stdarg.h>
#include "avformat.h"
#include "dvdata.h"
#include "dv.h"
#include "fifo.h"

struct DVMuxContext {
    const DVprofile*  sys;    /* Current DV profile. E.g.: 525/60, 625/50 */
    int         n_ast;        /* Number of stereo audio streams (up to 2) */
    AVStream   *ast[2];       /* Stereo audio streams */
    AVFifoBuffer  audio_data[2]; /* Fifo for storing excessive amounts of PCM */
    int         frames;       /* Number of a current frame */
    time_t      start_time;   /* Start time of recording */
    int         has_audio;    /* frame under contruction has audio */
    int         has_video;    /* frame under contruction has video */
    uint8_t     frame_buf[DV_MAX_FRAME_SIZE]; /* frame under contruction */
};

static const int dv_aaux_packs_dist[12][9] = {
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
    { 0xff, 0xff, 0xff, 0x50, 0x51, 0x52, 0x53, 0xff, 0xff },
    { 0x50, 0x51, 0x52, 0x53, 0xff, 0xff, 0xff, 0xff, 0xff },
};

static int dv_audio_frame_size(const DVprofile* sys, int frame)
{
    return sys->audio_samples_dist[frame % (sizeof(sys->audio_samples_dist)/
                                            sizeof(sys->audio_samples_dist[0]))];
}

static int dv_write_pack(enum dv_pack_type pack_id, DVMuxContext *c, uint8_t* buf, ...)
{
    struct tm tc;
    time_t ct;
    int ltc_frame;
    va_list ap;

    buf[0] = (uint8_t)pack_id;
    switch (pack_id) {
    case dv_timecode:
        ct = (time_t)(c->frames / ((float)c->sys->frame_rate /
                                   (float)c->sys->frame_rate_base));
        brktimegm(ct, &tc);
        /*
         * LTC drop-frame frame counter drops two frames (0 and 1) every
         * minute, unless it is exactly divisible by 10
         */
        ltc_frame = (c->frames + 2*ct/60 - 2*ct/600) % c->sys->ltc_divisor;
        buf[1] = (0 << 7) | /* Color fame: 0 - unsync; 1 - sync mode */
                 (1 << 6) | /* Drop frame timecode: 0 - nondrop; 1 - drop */
                 ((ltc_frame / 10) << 4) | /* Tens of frames */
                 (ltc_frame % 10);         /* Units of frames */
        buf[2] = (1 << 7) | /* Biphase mark polarity correction: 0 - even; 1 - odd */
                 ((tc.tm_sec / 10) << 4) | /* Tens of seconds */
                 (tc.tm_sec % 10);         /* Units of seconds */
        buf[3] = (1 << 7) | /* Binary group flag BGF0 */
                 ((tc.tm_min / 10) << 4) | /* Tens of minutes */
                 (tc.tm_min % 10);         /* Units of minutes */
        buf[4] = (1 << 7) | /* Binary group flag BGF2 */
                 (1 << 6) | /* Binary group flag BGF1 */
                 ((tc.tm_hour / 10) << 4) | /* Tens of hours */
                 (tc.tm_hour % 10);         /* Units of hours */
        break;
    case dv_audio_source:  /* AAUX source pack */
        va_start(ap, buf);
        buf[1] = (1 << 7) | /* locked mode -- SMPTE only supports locked mode */
                 (1 << 6) | /* reserved -- always 1 */
                 (dv_audio_frame_size(c->sys, c->frames) -
                  c->sys->audio_min_samples[0]);
                            /* # of samples      */
        buf[2] = (0 << 7) | /* multi-stereo      */
                 (0 << 5) | /* #of audio channels per block: 0 -- 1 channel */
                 (0 << 4) | /* pair bit: 0 -- one pair of channels */
                 !!va_arg(ap, int); /* audio mode        */
        buf[3] = (1 << 7) | /* res               */
                 (1 << 6) | /* multi-language flag */
                 (c->sys->dsf << 5) | /*  system: 60fields/50fields */
                 (c->sys->n_difchan & 2); /* definition: 0 -- 25Mbps, 2 -- 50Mbps */
        buf[4] = (1 << 7) | /* emphasis: 1 -- off */
                 (0 << 6) | /* emphasis time constant: 0 -- reserved */
                 (0 << 3) | /* frequency: 0 -- 48Khz, 1 -- 44,1Khz, 2 -- 32Khz */
                  0;        /* quantization: 0 -- 16bit linear, 1 -- 12bit nonlinear */
        va_end(ap);
        break;
    case dv_audio_control:
        buf[1] = (0 << 6) | /* copy protection: 0 -- unrestricted */
                 (1 << 4) | /* input source: 1 -- digital input */
                 (3 << 2) | /* compression: 3 -- no information */
                  0;        /* misc. info/SMPTE emphasis off */
        buf[2] = (1 << 7) | /* recording start point: 1 -- no */
                 (1 << 6) | /* recording end point: 1 -- no */
                 (1 << 3) | /* recording mode: 1 -- original */
                  7;
        buf[3] = (1 << 7) | /* direction: 1 -- forward */
                 (c->sys->pix_fmt == PIX_FMT_YUV420P ? 0x20 : /* speed */
                                                       c->sys->ltc_divisor*4);
        buf[4] = (1 << 7) | /* reserved -- always 1 */
                  0x7f;     /* genre category */
        break;
    case dv_audio_recdate:
    case dv_video_recdate:  /* VAUX recording date */
        ct = c->start_time + (time_t)(c->frames /
             ((float)c->sys->frame_rate / (float)c->sys->frame_rate_base));
        brktimegm(ct, &tc);
        buf[1] = 0xff; /* ds, tm, tens of time zone, units of time zone */
                       /* 0xff is very likely to be "unknown" */
        buf[2] = (3 << 6) | /* reserved -- always 1 */
                 ((tc.tm_mday / 10) << 4) | /* Tens of day */
                 (tc.tm_mday % 10);         /* Units of day */
        buf[3] = /* we set high 4 bits to 0, shouldn't we set them to week? */
                 ((tc.tm_mon / 10) << 4) |    /* Tens of month */
                 (tc.tm_mon  % 10);           /* Units of month */
        buf[4] = (((tc.tm_year % 100) / 10) << 4) | /* Tens of year */
                 (tc.tm_year % 10);                 /* Units of year */
        break;
    case dv_audio_rectime:  /* AAUX recording time */
    case dv_video_rectime:  /* VAUX recording time */
        ct = c->start_time + (time_t)(c->frames /
             ((float)c->sys->frame_rate / (float)c->sys->frame_rate_base));
        brktimegm(ct, &tc);
        buf[1] = (3 << 6) | /* reserved -- always 1 */
                 0x3f; /* tens of frame, units of frame: 0x3f - "unknown" ? */
        buf[2] = (1 << 7) | /* reserved -- always 1 */
                 ((tc.tm_sec / 10) << 4) | /* Tens of seconds */
                 (tc.tm_sec % 10);         /* Units of seconds */
        buf[3] = (1 << 7) | /* reserved -- always 1 */
                 ((tc.tm_min / 10) << 4) | /* Tens of minutes */
                 (tc.tm_min % 10);         /* Units of minutes */
        buf[4] = (3 << 6) | /* reserved -- always 1 */
                 ((tc.tm_hour / 10) << 4) | /* Tens of hours */
                 (tc.tm_hour % 10);         /* Units of hours */
        break;
    default:
        buf[1] = buf[2] = buf[3] = buf[4] = 0xff;
    }
    return 5;
}

static void dv_inject_audio(DVMuxContext *c, int channel, uint8_t* frame_ptr)
{
    int i, j, d, of, size;
    size = 4 * dv_audio_frame_size(c->sys, c->frames);
    frame_ptr += channel * c->sys->difseg_size * 150 * 80;
    for (i = 0; i < c->sys->difseg_size; i++) {
        frame_ptr += 6 * 80; /* skip DIF segment header */
        for (j = 0; j < 9; j++) {
            dv_write_pack(dv_aaux_packs_dist[i][j], c, &frame_ptr[3], i >= c->sys->difseg_size/2);
            for (d = 8; d < 80; d+=2) {
                of = c->sys->audio_shuffle[i][j] + (d - 8)/2 * c->sys->audio_stride;
                if (of*2 >= size)
                    continue;

                frame_ptr[d] = av_fifo_peek(&c->audio_data[channel], of*2+1); // FIXME: may be we have to admit
                frame_ptr[d+1] = av_fifo_peek(&c->audio_data[channel], of*2); //        that DV is a big endian PCM
            }
            frame_ptr += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
        }
    }
}

static void dv_inject_metadata(DVMuxContext *c, uint8_t* frame)
{
    int j, k;
    uint8_t* buf;

    for (buf = frame; buf < frame + c->sys->frame_size; buf += 150 * 80) {
        /* DV subcode: 2nd and 3d DIFs */
        for (j = 80; j < 80 * 3; j += 80) {
            for (k = 6; k < 6 * 8; k += 8)