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/*
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 * IEC 61937 muxer
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 * Copyright (c) 2009 Bartlomiej Wolowiec
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 * Copyright (c) 2010 Anssi Hannula
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 * Copyright (c) 2010 Carl Eugen Hoyos
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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
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 * IEC-61937 encapsulation of various formats, used by S/PDIF
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 * @author Bartlomiej Wolowiec
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 * @author Anssi Hannula
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 * @author Carl Eugen Hoyos
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 */
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/*
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 * Terminology used in specification:
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 * data-burst - IEC61937 frame, contains header and encapsuled frame
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 * burst-preambule - IEC61937 frame header, contains 16-bits words named Pa, Pb, Pc and Pd
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 * burst-payload - encapsuled frame
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 * Pa, Pb - syncword - 0xF872, 0x4E1F
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 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
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 *      and bitstream number (bits 13-15)
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 * data-type - determines type of encapsuled frames
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 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
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 *
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 * IEC 61937 frames at normal usage start every specific count of bytes,
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 *      dependent from data-type (spaces between packets are filled by zeros)
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 */
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#include "avformat.h"
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#include "spdif.h"
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#include "libavcodec/ac3.h"
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#include "libavcodec/dca.h"
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#include "libavcodec/aacadtsdec.h"
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typedef struct IEC61937Context {
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    enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
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    int length_code;                ///< length code in bits or bytes, depending on data type
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    int pkt_offset;                 ///< data burst repetition period in bytes
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    uint8_t *buffer;                ///< allocated buffer, used for swap bytes
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    int buffer_size;                ///< size of allocated buffer
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    uint8_t *out_buf;               ///< pointer to the outgoing data before byte-swapping
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    int out_bytes;                  ///< amount of outgoing bytes
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    int use_preamble;               ///< preamble enabled (disabled for exactly pre-padded DTS)
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    int extra_bswap;                ///< extra bswap for payload (for LE DTS => standard BE DTS)
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    uint8_t *hd_buf;                ///< allocated buffer to concatenate hd audio frames
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    int hd_buf_size;                ///< size of the hd audio buffer
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    int hd_buf_count;               ///< number of frames in the hd audio buffer
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    int hd_buf_filled;              ///< amount of bytes in the hd audio buffer
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    /// function, which generates codec dependent header information.
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    /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
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    int (*header_info) (AVFormatContext *s, AVPacket *pkt);
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} IEC61937Context;
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static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    int bitstream_mode = pkt->data[5] & 0x7;
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    ctx->data_type  = IEC61937_AC3 | (bitstream_mode << 8);
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    ctx->pkt_offset = AC3_FRAME_SIZE << 2;
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    return 0;
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}
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static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
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    int repeat = 1;
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    if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
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        repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
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    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
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    if (!ctx->hd_buf)
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        return AVERROR(ENOMEM);
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    memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
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    ctx->hd_buf_filled += pkt->size;
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    if (++ctx->hd_buf_count < repeat){
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        ctx->pkt_offset = 0;
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        return 0;
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    }
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    ctx->data_type   = IEC61937_EAC3;
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    ctx->pkt_offset  = 24576;
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    ctx->out_buf     = ctx->hd_buf;
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    ctx->out_bytes   = ctx->hd_buf_filled;
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    ctx->length_code = ctx->hd_buf_filled;
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    ctx->hd_buf_count  = 0;
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    ctx->hd_buf_filled = 0;
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    return 0;
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}
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static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    uint32_t syncword_dts = AV_RB32(pkt->data);
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    int blocks;
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    switch (syncword_dts) {
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    case DCA_MARKER_RAW_BE:
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        blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
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        break;
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    case DCA_MARKER_RAW_LE:
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        blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
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        ctx->extra_bswap = 1;
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        break;
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    case DCA_MARKER_14B_BE:
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        blocks =
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            (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
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        break;
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    case DCA_MARKER_14B_LE:
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        blocks =
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            (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
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        ctx->extra_bswap = 1;
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        break;
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    default:
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        av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
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        return AVERROR_INVALIDDATA;
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    }
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    blocks++;
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    switch (blocks) {
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    case  512 >> 5: ctx->data_type = IEC61937_DTS1; break;
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    case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
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    case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
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    default:
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        av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
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               blocks << 5);
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        return AVERROR(ENOSYS);
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    }
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    ctx->pkt_offset = blocks << 7;
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    if (ctx->out_bytes == ctx->pkt_offset) {
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        /* The DTS stream fits exactly into the output stream, so skip the
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         * preamble as it would not fit in there. This is the case for dts
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         * discs and dts-in-wav. */
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        ctx->use_preamble = 0;
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    }
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    return 0;
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}
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static const enum IEC61937DataType mpeg_data_type[2][3] = {
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    //     LAYER1                      LAYER2                  LAYER3
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    { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF },//MPEG2 LSF
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    { IEC61937_MPEG1_LAYER1,     IEC61937_MPEG1_LAYER23,    IEC61937_MPEG1_LAYER23 },   //MPEG1
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};
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static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    int version =      (pkt->data[1] >> 3) & 3;
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    int layer   = 3 - ((pkt->data[1] >> 1) & 3);
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    int extension = pkt->data[2] & 1;
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    if (layer == 3 || version == 1) {
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        av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
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        return AVERROR_INVALIDDATA;
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    }
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    av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
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    if (version == 2 && extension) {
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        ctx->data_type  = IEC61937_MPEG2_EXT;
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        ctx->pkt_offset = 4608;
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    } else {
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        ctx->data_type  = mpeg_data_type [version & 1][layer];
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        ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
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    }
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    // TODO Data type dependant info (normal/karaoke, dynamic range control)
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    return 0;
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}
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static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    AACADTSHeaderInfo hdr;
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    GetBitContext gbc;
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    int ret;
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    init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
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    ret = ff_aac_parse_header(&gbc, &hdr);
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    if (ret < 0) {
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        av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
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        return AVERROR_INVALIDDATA;
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    }
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    ctx->pkt_offset = hdr.samples << 2;
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    switch (hdr.num_aac_frames) {
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    case 1:
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        ctx->data_type = IEC61937_MPEG2_AAC;
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        break;
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    case 2:
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        ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;
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        break;
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    case 4:
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        ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;
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        break;
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    default:
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        av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
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               hdr.samples);
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        return AVERROR(EINVAL);
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    }
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    //TODO Data type dependent info (LC profile/SBR)
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    return 0;
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}
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/*
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 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
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 * they can be encapsulated in IEC 61937.
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 * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
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 * to achieve constant rate.
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 * The actual format of a MAT frame is unknown, but the below seems to work.
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 * However, it seems it is not actually necessary for the 24 TrueHD frames to
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 * be in an exact alignment with the MAT frame.
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 */
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#define MAT_FRAME_SIZE          61424
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#define TRUEHD_FRAME_OFFSET     2560
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#define MAT_MIDDLE_CODE_OFFSET  -4
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static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    int mat_code_length = 0;
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    const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
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    if (!ctx->hd_buf_count) {
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        const char mat_start_code[20] = { 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83, 0x49, 0x80, 0x77, 0xE0 };
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        mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
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        memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
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    } else if (ctx->hd_buf_count == 12) {
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        const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
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        mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
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        memcpy(&ctx->hd_buf[12 * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + MAT_MIDDLE_CODE_OFFSET],
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               mat_middle_code, sizeof(mat_middle_code));
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    }
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    if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
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        /* if such frames exist, we'd need some more complex logic to
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         * distribute the TrueHD frames in the MAT frame */
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        av_log(s, AV_LOG_ERROR, "TrueHD frame too big, %d bytes\n", pkt->size);
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        av_log_ask_for_sample(s, NULL);
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        return AVERROR_INVALIDDATA;
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    }
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    memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
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           pkt->data, pkt->size);
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    memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
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           0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
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    if (++ctx->hd_buf_count < 24){
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        ctx->pkt_offset = 0;
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        return 0;
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    }
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    memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
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    ctx->hd_buf_count = 0;
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    ctx->data_type   = IEC61937_TRUEHD;
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    ctx->pkt_offset  = 61440;
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    ctx->out_buf     = ctx->hd_buf;
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    ctx->out_bytes   = MAT_FRAME_SIZE;
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    ctx->length_code = MAT_FRAME_SIZE;
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    return 0;
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}
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static int spdif_write_header(AVFormatContext *s)
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{
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    IEC61937Context *ctx = s->priv_data;
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    switch (s->streams[0]->codec->codec_id) {
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    case CODEC_ID_AC3:
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        ctx->header_info = spdif_header_ac3;
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        break;
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    case CODEC_ID_EAC3:
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        ctx->header_info = spdif_header_eac3;
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        break;
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    case CODEC_ID_MP1:
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    case CODEC_ID_MP2:
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    case CODEC_ID_MP3:
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        ctx->header_info = spdif_header_mpeg;
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        break;
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    case CODEC_ID_DTS:
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        ctx->header_info = spdif_header_dts;
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        break;
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    case CODEC_ID_AAC:
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        ctx->header_info = spdif_header_aac;
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        break;
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    case CODEC_ID_TRUEHD:
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        ctx->header_info = spdif_header_truehd;
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        ctx->hd_buf = av_malloc(MAT_FRAME_SIZE);
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        if (!ctx->hd_buf)
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            return AVERROR(ENOMEM);
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        break;
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    default:
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        av_log(s, AV_LOG_ERROR, "codec not supported\n");
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        return AVERROR_PATCHWELCOME;
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    }
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    return 0;
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}
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static int spdif_write_trailer(AVFormatContext *s)
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{
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    IEC61937Context *ctx = s->priv_data;
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    av_freep(&ctx->buffer);
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    av_freep(&ctx->hd_buf);
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    return 0;
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}
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static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
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{
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    IEC61937Context *ctx = s->priv_data;
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    int ret, padding;
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    ctx->out_buf = pkt->data;
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    ctx->out_bytes = pkt->size;
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    ctx->length_code = FFALIGN(pkt->size, 2) << 3;
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    ctx->use_preamble = 1;
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    ctx->extra_bswap = 0;
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    ret = ctx->header_info(s, pkt);
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    if (ret < 0)
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        return ret;
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    if (!ctx->pkt_offset)
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        return 0;
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    padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
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    if (padding < 0) {
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        av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
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        return AVERROR(EINVAL);
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    }
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    if (ctx->use_preamble) {
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        put_le16(s->pb, SYNCWORD1);       //Pa
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        put_le16(s->pb, SYNCWORD2);       //Pb
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        put_le16(s->pb, ctx->data_type);  //Pc
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        put_le16(s->pb, ctx->length_code);//Pd
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    }
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    if (HAVE_BIGENDIAN ^ ctx->extra_bswap) {
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    put_buffer(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
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    } else {
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    av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + FF_INPUT_BUFFER_PADDING_SIZE);
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    if (!ctx->buffer)
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        return AVERROR(ENOMEM);
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    ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
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    put_buffer(s->pb, ctx->buffer, ctx->out_bytes & ~1);
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    }
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    if (ctx->out_bytes & 1)
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        put_be16(s->pb, ctx->out_buf[ctx->out_bytes - 1]);
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    put_nbyte(s->pb, 0, padding);
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    av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
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           ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
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381
    put_flush_packet(s->pb);
382
    return 0;
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}
384

    
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AVOutputFormat spdif_muxer = {
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    "spdif",
387
    NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
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    NULL,
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    "spdif",
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    sizeof(IEC61937Context),
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    CODEC_ID_AC3,
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    CODEC_ID_NONE,
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    spdif_write_header,
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    spdif_write_packet,
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    spdif_write_trailer,
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};