ffmpeg/libavformat/mxfenc.c

/*
 * MXF muxer
 * Copyright (c) 2008 GUCAS, Zhentan Feng <spyfeng at gmail dot com>
 *
 * 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
 */

/*
 * References
 * SMPTE 336M KLV Data Encoding Protocol Using Key-Length-Value
 * SMPTE 377M MXF File Format Specifications
 * SMPTE 379M MXF Generic Container
 * SMPTE 381M Mapping MPEG Streams into the MXF Generic Container
 * SMPTE RP210: SMPTE Metadata Dictionary
 * SMPTE RP224: Registry of SMPTE Universal Labels
 */

//#define DEBUG

#include "mxf.h"

typedef struct {
    int local_tag;
    UID uid;
} MXFLocalTagPair;

static const uint8_t uuid_base[]            = { 0xAD,0xAB,0x44,0x24,0x2f,0x25,0x4d,0xc7,0x92,0xff,0x29,0xbd };
static const uint8_t umid_base[]            = { 0x06,0x0A,0x2B,0x34,0x01,0x01,0x01,0x01,0x01,0x01,0x0F,0x00,0x13,0x00,0x00,0x00 };

/**
 * complete key for operation pattern, partitions, and primer pack
 */
static const uint8_t op1a_ul[]              = { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x01,0x0D,0x01,0x02,0x01,0x01,0x01,0x01,0x00 };
static const uint8_t header_partition_key[] = { 0x06,0x0E,0x2B,0x34,0x02,0x05,0x01,0x01,0x0D,0x01,0x02,0x01,0x01,0x02,0x04,0x00 }; // ClosedComplete
static const uint8_t footer_partition_key[] = { 0x06,0x0E,0x2B,0x34,0x02,0x05,0x01,0x01,0x0D,0x01,0x02,0x01,0x01,0x04,0x04,0x00 }; // ClosedComplete
static const uint8_t primer_pack_key[]      = { 0x06,0x0E,0x2B,0x34,0x02,0x05,0x01,0x01,0x0D,0x01,0x02,0x01,0x01,0x05,0x01,0x00 };

static void mxf_write_uuid(ByteIOContext *pb, enum CodecID type, int value)
{
    put_buffer(pb, uuid_base, 12);
    put_be16(pb, type);
    put_be16(pb, value);
}

static int klv_encode_ber_length(ByteIOContext *pb, uint64_t len)
{
    // Determine the best BER size
    int size;
    if (len < 128) {
        //short form
        put_byte(pb, len);
        return 1;
    }

    size = (av_log2(len) >> 3) + 1;

    // long form
    put_byte(pb, 0x80 + size);
    while(size) {
        size --;
        put_byte(pb, len >> 8 * size & 0xff);
    }
    return 0;
}

static const MXFCodecUL *mxf_get_essence_container_ul(enum CodecID type)
{
    const MXFCodecUL *uls = ff_mxf_essence_container_uls;
    while (uls->id != CODEC_ID_NONE) {
        if (uls->id == type)
            break;
        uls++;
    }
    return uls;
}

static int mxf_write_primer_pack(AVFormatContext *s)
{
    ByteIOContext *pb = s->pb;
    int local_tag_number, i = 0;

    local_tag_number = sizeof(mxf_local_tag_batch) / sizeof(MXFLocalTagPair);

    put_buffer(pb, primer_pack_key, 16);
    klv_encode_ber_length(pb, local_tag_number * 18 + 8);

    put_be32(pb, local_tag_number); // local_tag num
    put_be32(pb, 18); // item size, always 18 according to the specs

    for (i = 0; i < local_tag_number; i++) {
        put_be16(pb, mxf_local_tag_batch[i].local_tag);
        put_buffer(pb, mxf_local_tag_batch[i].uid, 16);
    }
    return 0;
}

static void mxf_write_local_tag(ByteIOContext *pb, int value_size, int tag)
{
    put_be16(pb, tag);
    put_be16(pb, value_size);
}

static void mxf_free(AVFormatContext *s)
{
    MXFContext *mxf = s->priv_data;
    AVStream *st;
    int i;

    for (i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        av_freep(&st->priv_data);
    }
    av_freep(&mxf->essence_container_uls);
}

static const MXFDataDefinitionUL *mxf_get_data_definition_ul(enum CodecType type)
{
    const MXFDataDefinitionUL *uls = ff_mxf_data_definition_uls;
    while (uls->type != CODEC_TYPE_DATA) {
        if (type == uls->type)
            break;
        uls ++;
    }
    return uls;
}

static int mux_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    ByteIOContext *pb = s->pb;
    AVStream *st = s->streams[pkt->stream_index];
    MXFStreamContext *sc = st->priv_data;

    put_buffer(pb, sc->track_essence_element_key, 16); // write key
    klv_encode_ber_length(pb, pkt->size); // write length
    put_buffer(pb, pkt->data, pkt->size); // write value

    put_flush_packet(pb);
    return 0;
}

AVOutputFormat mxf_muxer = {
    "mxf",
    NULL_IF_CONFIG_SMALL("Material eXchange Format"),
    NULL,
    "mxf",
    sizeof(MXFContext),
    CODEC_ID_PCM_S16LE,
    CODEC_ID_MPEG2VIDEO,
    mux_write_header,
    mux_write_packet,
    mux_write_footer,
};