PeerStreamer

/*

 * QCP format (.qcp) demuxer

 * Copyright (c) 2009 Kenan Gillet

 *

 * 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

 * QCP format (.qcp) demuxer

 * @author Kenan Gillet

 * @sa RFC 3625: "The QCP File Format and Media Types for Speech Data"

 *     http://tools.ietf.org/html/rfc3625

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

typedef struct {

    uint32_t data_size;                     ///< size of data chunk

#define QCP_MAX_MODE 4

    int16_t rates_per_mode[QCP_MAX_MODE+1]; ///< contains the packet size corresponding

                                            ///< to each mode, -1 if no size.

} QCPContext;

/**

 * Last 15 out of 16 bytes of QCELP-13K GUID, as stored in the file;

 * the first byte of the GUID can be either 0x41 or 0x42.

 */

static const uint8_t guid_qcelp_13k_part[15] = {

    0x6d, 0x7f, 0x5e, 0x15, 0xb1, 0xd0, 0x11, 0xba,

    0x91, 0x00, 0x80, 0x5f, 0xb4, 0xb9, 0x7e

};

/**

 * EVRC GUID as stored in the file

 */

static const uint8_t guid_evrc[16] = {

    0x8d, 0xd4, 0x89, 0xe6, 0x76, 0x90, 0xb5, 0x46,

    0x91, 0xef, 0x73, 0x6a, 0x51, 0x00, 0xce, 0xb4

};

/**

 * SMV GUID as stored in the file

 */

static const uint8_t guid_smv[16] = {

    0x75, 0x2b, 0x7c, 0x8d, 0x97, 0xa7, 0x49, 0xed,

    0x98, 0x5e, 0xd5, 0x3c, 0x8c, 0xc7, 0x5f, 0x84

};

/**

 * @param guid contains at least 16 bytes

 * @return 1 if the guid is a qcelp_13k guid, 0 otherwise

 */

static int is_qcelp_13k_guid(const uint8_t *guid) {

    return (guid[0] == 0x41 || guid[0] == 0x42)

        && !memcmp(guid+1, guid_qcelp_13k_part, sizeof(guid_qcelp_13k_part));

}

static int qcp_probe(AVProbeData *pd)

{

    if (AV_RL32(pd->buf  ) == AV_RL32("RIFF") &&

        AV_RL64(pd->buf+8) == AV_RL64("QLCMfmt "))

        return AVPROBE_SCORE_MAX;

    return 0;

}

static int qcp_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    AVIOContext *pb = s->pb;

    QCPContext    *c  = s->priv_data;

    AVStream      *st = av_new_stream(s, 0);

    uint8_t       buf[16];

    int           i, nb_rates;

    if (!st)

        return AVERROR(ENOMEM);

    avio_rb32(pb);                    // "RIFF"

    s->file_size = avio_rl32(pb) + 8;

    avio_skip(pb, 8 + 4 + 1 + 1);    // "QLCMfmt " + chunk-size + major-version + minor-version

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codec->channels   = 1;

    avio_read(pb, buf, 16);

    if (is_qcelp_13k_guid(buf)) {

        st->codec->codec_id = CODEC_ID_QCELP;

    } else if (!memcmp(buf, guid_evrc, 16)) {

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

        return AVERROR_PATCHWELCOME;

    } else if (!memcmp(buf, guid_smv, 16)) {

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

        return AVERROR_PATCHWELCOME;

    } else {

        av_log(s, AV_LOG_ERROR, "Unknown codec GUID.\n");

        return AVERROR_INVALIDDATA;

    }

    avio_skip(pb, 2 + 80); // codec-version + codec-name

    st->codec->bit_rate = avio_rl16(pb);

    s->packet_size = avio_rl16(pb);

    avio_skip(pb, 2); // block-size

    st->codec->sample_rate = avio_rl16(pb);

    avio_skip(pb, 2); // sample-size

    memset(c->rates_per_mode, -1, sizeof(c->rates_per_mode));

    nb_rates = avio_rl32(pb);

    nb_rates = FFMIN(nb_rates, 8);

    for (i=0; i<nb_rates; i++) {

        int size = avio_r8(pb);

        int mode = avio_r8(pb);

        if (mode > QCP_MAX_MODE) {

            av_log(s, AV_LOG_WARNING, "Unknown entry %d=>%d in rate-map-table.\n ", mode, size);

        } else

            c->rates_per_mode[mode] = size;

    }

    avio_skip(pb, 16 - 2*nb_rates + 20); // empty entries of rate-map-table + reserved

    return 0;

}

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

{

    AVIOContext *pb = s->pb;

    QCPContext    *c  = s->priv_data;

    unsigned int  chunk_size, tag;

    while(!pb->eof_reached) {

        if (c->data_size) {

            int pkt_size, ret, mode = avio_r8(pb);

            if (s->packet_size) {

                pkt_size = s->packet_size - 1;

            } else if (mode > QCP_MAX_MODE || (pkt_size = c->rates_per_mode[mode]) < 0) {

                c->data_size--;

                continue;

            }

            if (c->data_size <= pkt_size) {

                av_log(s, AV_LOG_WARNING, "Data chunk is too small.\n");

                pkt_size = c->data_size - 1;

            }

            if ((ret = av_get_packet(pb, pkt, pkt_size)) >= 0) {

                if (pkt_size != ret)

                    av_log(s, AV_LOG_ERROR, "Packet size is too small.\n");

                c->data_size -= pkt_size + 1;

            }

            return ret;

        }

        if (avio_tell(pb) & 1 && avio_r8(pb))

            av_log(s, AV_LOG_WARNING, "Padding should be 0.\n");

        tag        = avio_rl32(pb);

        chunk_size = avio_rl32(pb);

        switch (tag) {

        case MKTAG('v', 'r', 'a', 't'):

            if (avio_rl32(pb)) // var-rate-flag

                s->packet_size = 0;

            avio_skip(pb, 4); // size-in-packets

            break;

        case MKTAG('d', 'a', 't', 'a'):

            c->data_size = chunk_size;

            break;

        default:

            avio_skip(pb, chunk_size);

        }

    }

    return AVERROR_EOF;

}

AVInputFormat ff_qcp_demuxer = {

    .name           = "qcp",

    .long_name      = NULL_IF_CONFIG_SMALL("QCP format"),

    .priv_data_size = sizeof(QCPContext),

    .read_probe     = qcp_probe,

    .read_header    = qcp_read_header,

    .read_packet    = qcp_read_packet,

};