PeerStreamer

/*

 * IEC 61937 muxer

 * Copyright (c) 2009 Bartlomiej Wolowiec

 * Copyright (c) 2010 Anssi Hannula

 * Copyright (c) 2010 Carl Eugen Hoyos

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * IEC-61937 encapsulation of various formats, used by S/PDIF

 * @author Bartlomiej Wolowiec

 * @author Anssi Hannula

 * @author Carl Eugen Hoyos

 */

/*

 * Terminology used in specification:

 * data-burst - IEC61937 frame, contains header and encapsuled frame

 * burst-preambule - IEC61937 frame header, contains 16-bits words named Pa, Pb, Pc and Pd

 * burst-payload - encapsuled frame

 * Pa, Pb - syncword - 0xF872, 0x4E1F

 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)

 *      and bitstream number (bits 13-15)

 * data-type - determines type of encapsuled frames

 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)

 *

 * IEC 61937 frames at normal usage start every specific count of bytes,

 *      dependent from data-type (spaces between packets are filled by zeros)

 */

#include "avformat.h"

#include "avio_internal.h"

#include "spdif.h"

#include "libavcodec/ac3.h"

#include "libavcodec/dca.h"

#include "libavcodec/dcadata.h"

#include "libavcodec/aacadtsdec.h"

#include "libavutil/opt.h"

typedef struct IEC61937Context {

    const AVClass *av_class;

    enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst

    int length_code;                ///< length code in bits or bytes, depending on data type

    int pkt_offset;                 ///< data burst repetition period in bytes

    uint8_t *buffer;                ///< allocated buffer, used for swap bytes

    int buffer_size;                ///< size of allocated buffer

    uint8_t *out_buf;               ///< pointer to the outgoing data before byte-swapping

    int out_bytes;                  ///< amount of outgoing bytes

    int use_preamble;               ///< preamble enabled (disabled for exactly pre-padded DTS)

    int extra_bswap;                ///< extra bswap for payload (for LE DTS => standard BE DTS)

    uint8_t *hd_buf;                ///< allocated buffer to concatenate hd audio frames

    int hd_buf_size;                ///< size of the hd audio buffer

    int hd_buf_count;               ///< number of frames in the hd audio buffer

    int hd_buf_filled;              ///< amount of bytes in the hd audio buffer

    int dtshd_skip;                 ///< counter used for skipping DTS-HD frames

    /* AVOptions: */

    int dtshd_rate;

    int dtshd_fallback;

#define SPDIF_FLAG_BIGENDIAN    0x01

    int spdif_flags;

    /// function, which generates codec dependent header information.

    /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary

    int (*header_info) (AVFormatContext *s, AVPacket *pkt);

} IEC61937Context;

static const AVOption options[] = {

{ "spdif_flags", "IEC 61937 encapsulation flags", offsetof(IEC61937Context, spdif_flags), FF_OPT_TYPE_FLAGS, {.dbl = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },

{ "be", "output in big-endian format (for use as s16be)", 0, FF_OPT_TYPE_CONST, {.dbl = SPDIF_FLAG_BIGENDIAN},  0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },

{ "dtshd_rate", "mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(IEC61937Context, dtshd_rate), FF_OPT_TYPE_INT, {.dbl = 0}, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },

{ "dtshd_fallback_time", "min secs to strip HD for after an overflow (-1: till the end, default 60)", offsetof(IEC61937Context, dtshd_fallback), FF_OPT_TYPE_INT, {.dbl = 60}, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },

{ NULL },

};

static const AVClass class = { "spdif", av_default_item_name, options, LIBAVUTIL_VERSION_INT };

static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    int bitstream_mode = pkt->data[5] & 0x7;

    ctx->data_type  = IEC61937_AC3 | (bitstream_mode << 8);

    ctx->pkt_offset = AC3_FRAME_SIZE << 2;

    return 0;

}

static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};

    int repeat = 1;

    if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */

        repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */

    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);

    if (!ctx->hd_buf)

        return AVERROR(ENOMEM);

    memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);

    ctx->hd_buf_filled += pkt->size;

    if (++ctx->hd_buf_count < repeat){

        ctx->pkt_offset = 0;

        return 0;

    }

    ctx->data_type   = IEC61937_EAC3;

    ctx->pkt_offset  = 24576;

    ctx->out_buf     = ctx->hd_buf;

    ctx->out_bytes   = ctx->hd_buf_filled;

    ctx->length_code = ctx->hd_buf_filled;

    ctx->hd_buf_count  = 0;

    ctx->hd_buf_filled = 0;

    return 0;

}

/*

 * DTS type IV (DTS-HD) can be transmitted with various frame repetition

 * periods; longer repetition periods allow for longer packets and therefore

 * higher bitrate. Longer repetition periods mean that the constant bitrate of

 * the outputted IEC 61937 stream is higher.

 * The repetition period is measured in IEC 60958 frames (4 bytes).

 */

static int spdif_dts4_subtype(int period)

{

    switch (period) {

    case 512:   return 0x0;

    case 1024:  return 0x1;

    case 2048:  return 0x2;

    case 4096:  return 0x3;

    case 8192:  return 0x4;

    case 16384: return 0x5;

    }

    return -1;

}

static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,

                             int sample_rate, int blocks)

{

    IEC61937Context *ctx = s->priv_data;

    static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };

    int pkt_size = pkt->size;

    int period;

    int subtype;

    if (!core_size) {

        av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");

        return AVERROR(EINVAL);

    }

    if (!sample_rate) {

        av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");

        return AVERROR_INVALIDDATA;

    }

    period = ctx->dtshd_rate * (blocks << 5) / sample_rate;

    subtype = spdif_dts4_subtype(period);

    if (subtype < 0) {

        av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "

               "impossible repetition period of %d for the current DTS stream"

               " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,

               blocks << 5, sample_rate);

        return AVERROR(EINVAL);

    }

    /* set pkt_offset and DTS IV subtype according to the requested output

     * rate */

    ctx->pkt_offset = period * 4;

    ctx->data_type = IEC61937_DTSHD | subtype << 8;

    /* If the bitrate is too high for transmitting at the selected

     * repetition period setting, strip DTS-HD until a good amount

     * of consecutive non-overflowing HD frames have been observed.

     * This generally only happens if the caller is cramming a Master

     * Audio stream into 192kHz IEC 60958 (which may or may not fit). */

    if (sizeof(dtshd_start_code) + 2 + pkt_size

            > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {

        if (!ctx->dtshd_skip)

            av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "

                                      "temporarily sending core only\n");

        if (ctx->dtshd_fallback > 0)

            ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);

        else

            /* skip permanently (dtshd_fallback == -1) or just once

             * (dtshd_fallback == 0) */

            ctx->dtshd_skip = 1;

    }

    if (ctx->dtshd_skip && core_size) {

        pkt_size = core_size;

        if (ctx->dtshd_fallback >= 0)

            --ctx->dtshd_skip;

    }

    ctx->out_bytes   = sizeof(dtshd_start_code) + 2 + pkt_size;

    ctx->length_code = ctx->out_bytes;

    av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);

    if (!ctx->hd_buf)

        return AVERROR(ENOMEM);

    ctx->out_buf = ctx->hd_buf;

    memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));

    AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);

    memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);

    return 0;

}

static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    uint32_t syncword_dts = AV_RB32(pkt->data);

    int blocks;

    int sample_rate = 0;

    int core_size = 0;

    if (pkt->size < 9)

        return AVERROR_INVALIDDATA;

    switch (syncword_dts) {

    case DCA_MARKER_RAW_BE:

        blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;

        core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;

        sample_rate = dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];

        break;

    case DCA_MARKER_RAW_LE:

        blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;

        ctx->extra_bswap = 1;

        break;

    case DCA_MARKER_14B_BE:

        blocks =

            (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));

        break;

    case DCA_MARKER_14B_LE:

        blocks =

            (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));

        ctx->extra_bswap = 1;

        break;

    case DCA_HD_MARKER:

        /* We only handle HD frames that are paired with core. However,

           sometimes DTS-HD streams with core have a stray HD frame without

           core in the beginning of the stream. */

        av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");

        return AVERROR_INVALIDDATA;

    default:

        av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);

        return AVERROR_INVALIDDATA;

    }

    blocks++;

    if (ctx->dtshd_rate)

        /* DTS type IV output requested */

        return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);

    switch (blocks) {

    case  512 >> 5: ctx->data_type = IEC61937_DTS1; break;

    case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;

    case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;

    default:

        av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",

               blocks << 5);

        return AVERROR(ENOSYS);

    }

    /* discard extraneous data by default */

    if (core_size && core_size < pkt->size) {

        ctx->out_bytes = core_size;

        ctx->length_code = core_size << 3;

    }

    ctx->pkt_offset = blocks << 7;

    if (ctx->out_bytes == ctx->pkt_offset) {

        /* The DTS stream fits exactly into the output stream, so skip the

         * preamble as it would not fit in there. This is the case for dts

         * discs and dts-in-wav. */

        ctx->use_preamble = 0;

    } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {

        av_log_ask_for_sample(s, "Unrecognized large DTS frame.");

        /* This will fail with a "bitrate too high" in the caller */

    }

    return 0;

}

static const enum IEC61937DataType mpeg_data_type[2][3] = {

    //     LAYER1                      LAYER2                  LAYER3

    { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF },//MPEG2 LSF

    { IEC61937_MPEG1_LAYER1,     IEC61937_MPEG1_LAYER23,    IEC61937_MPEG1_LAYER23 },   //MPEG1

};

static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    int version =      (pkt->data[1] >> 3) & 3;

    int layer   = 3 - ((pkt->data[1] >> 1) & 3);

    int extension = pkt->data[2] & 1;

    if (layer == 3 || version == 1) {

        av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");

        return AVERROR_INVALIDDATA;

    }

    av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);

    if (version == 2 && extension) {

        ctx->data_type  = IEC61937_MPEG2_EXT;

        ctx->pkt_offset = 4608;

    } else {

        ctx->data_type  = mpeg_data_type [version & 1][layer];

        ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];

    }

    // TODO Data type dependant info (normal/karaoke, dynamic range control)

    return 0;

}

static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    AACADTSHeaderInfo hdr;

    GetBitContext gbc;

    int ret;

    init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);

    ret = ff_aac_parse_header(&gbc, &hdr);

    if (ret < 0) {

        av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");

        return AVERROR_INVALIDDATA;

    }

    ctx->pkt_offset = hdr.samples << 2;

    switch (hdr.num_aac_frames) {

    case 1:

        ctx->data_type = IEC61937_MPEG2_AAC;

        break;

    case 2:

        ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;

        break;

    case 4:

        ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;

        break;

    default:

        av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",

               hdr.samples);

        return AVERROR(EINVAL);

    }

    //TODO Data type dependent info (LC profile/SBR)

    return 0;

}

/*

 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before

 * they can be encapsulated in IEC 61937.

 * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them

 * to achieve constant rate.

 * The actual format of a MAT frame is unknown, but the below seems to work.

 * However, it seems it is not actually necessary for the 24 TrueHD frames to

 * be in an exact alignment with the MAT frame.

 */

#define MAT_FRAME_SIZE          61424

#define TRUEHD_FRAME_OFFSET     2560

#define MAT_MIDDLE_CODE_OFFSET  -4

static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    int mat_code_length = 0;

    const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };

    if (!ctx->hd_buf_count) {

        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 };

        mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;

        memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));

    } else if (ctx->hd_buf_count == 12) {

        const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };

        mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;

        memcpy(&ctx->hd_buf[12 * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + MAT_MIDDLE_CODE_OFFSET],

               mat_middle_code, sizeof(mat_middle_code));

    }

    if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {

        /* if such frames exist, we'd need some more complex logic to

         * distribute the TrueHD frames in the MAT frame */

        av_log(s, AV_LOG_ERROR, "TrueHD frame too big, %d bytes\n", pkt->size);

        av_log_ask_for_sample(s, NULL);

        return AVERROR_INVALIDDATA;

    }

    memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],

           pkt->data, pkt->size);

    memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],

           0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);

    if (++ctx->hd_buf_count < 24){

        ctx->pkt_offset = 0;

        return 0;

    }

    memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));

    ctx->hd_buf_count = 0;

    ctx->data_type   = IEC61937_TRUEHD;

    ctx->pkt_offset  = 61440;

    ctx->out_buf     = ctx->hd_buf;

    ctx->out_bytes   = MAT_FRAME_SIZE;

    ctx->length_code = MAT_FRAME_SIZE;

    return 0;

}

static int spdif_write_header(AVFormatContext *s)

{

    IEC61937Context *ctx = s->priv_data;

    switch (s->streams[0]->codec->codec_id) {

    case CODEC_ID_AC3:

        ctx->header_info = spdif_header_ac3;

        break;

    case CODEC_ID_EAC3:

        ctx->header_info = spdif_header_eac3;

        break;

    case CODEC_ID_MP1:

    case CODEC_ID_MP2:

    case CODEC_ID_MP3:

        ctx->header_info = spdif_header_mpeg;

        break;

    case CODEC_ID_DTS:

        ctx->header_info = spdif_header_dts;

        break;

    case CODEC_ID_AAC:

        ctx->header_info = spdif_header_aac;

        break;

    case CODEC_ID_TRUEHD:

        ctx->header_info = spdif_header_truehd;

        ctx->hd_buf = av_malloc(MAT_FRAME_SIZE);

        if (!ctx->hd_buf)

            return AVERROR(ENOMEM);

        break;

    default:

        av_log(s, AV_LOG_ERROR, "codec not supported\n");

        return AVERROR_PATCHWELCOME;

    }

    return 0;

}

static int spdif_write_trailer(AVFormatContext *s)

{

    IEC61937Context *ctx = s->priv_data;

    av_freep(&ctx->buffer);

    av_freep(&ctx->hd_buf);

    return 0;

}

static av_always_inline void spdif_put_16(IEC61937Context *ctx,

                                          AVIOContext *pb, unsigned int val)

{

    if (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)

        avio_wb16(pb, val);

    else

        avio_wl16(pb, val);

}

static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)

{

    IEC61937Context *ctx = s->priv_data;

    int ret, padding;

    ctx->out_buf = pkt->data;

    ctx->out_bytes = pkt->size;

    ctx->length_code = FFALIGN(pkt->size, 2) << 3;

    ctx->use_preamble = 1;

    ctx->extra_bswap = 0;

    ret = ctx->header_info(s, pkt);

    if (ret < 0)

        return ret;

    if (!ctx->pkt_offset)

        return 0;

    padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;

    if (padding < 0) {

        av_log(s, AV_LOG_ERROR, "bitrate is too high\n");

        return AVERROR(EINVAL);

    }

    if (ctx->use_preamble) {

        spdif_put_16(ctx, s->pb, SYNCWORD1);       //Pa

        spdif_put_16(ctx, s->pb, SYNCWORD2);       //Pb

        spdif_put_16(ctx, s->pb, ctx->data_type);  //Pc

        spdif_put_16(ctx, s->pb, ctx->length_code);//Pd

    }

    if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {

    avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);

    } else {

    av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + FF_INPUT_BUFFER_PADDING_SIZE);

    if (!ctx->buffer)

        return AVERROR(ENOMEM);

    ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);

    avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);

    }

    /* a final lone byte has to be MSB aligned */

    if (ctx->out_bytes & 1)

        spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);

    ffio_fill(s->pb, 0, padding);

    av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",

           ctx->data_type, ctx->out_bytes, ctx->pkt_offset);

    avio_flush(s->pb);

    return 0;

}

AVOutputFormat ff_spdif_muxer = {

    "spdif",

    NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),

    NULL,

    "spdif",

    sizeof(IEC61937Context),

    CODEC_ID_AC3,

    CODEC_ID_NONE,

    spdif_write_header,

    spdif_write_packet,

    spdif_write_trailer,

    .flags = AVFMT_NOTIMESTAMPS,

    .priv_class = &class,

};