PeerStreamer

/*

 * WavPack demuxer

 * Copyright (c) 2006 Konstantin Shishkov.

 *

 * 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 "libavutil/intreadwrite.h"

#include "avformat.h"

// specs say that maximum block size is 1Mb

#define WV_BLOCK_LIMIT 1047576

#define WV_EXTRA_SIZE 12

enum WV_FLAGS{

    WV_MONO   = 0x0004,

    WV_HYBRID = 0x0008,

    WV_JOINT  = 0x0010,

    WV_CROSSD = 0x0020,

    WV_HSHAPE = 0x0040,

    WV_FLOAT  = 0x0080,

    WV_INT32  = 0x0100,

    WV_HBR    = 0x0200,

    WV_HBAL   = 0x0400,

    WV_MCINIT = 0x0800,

    WV_MCEND  = 0x1000,

};

static const int wv_rates[16] = {

     6000,  8000,  9600, 11025, 12000, 16000, 22050, 24000,

    32000, 44100, 48000, 64000, 88200, 96000, 192000, -1

};

typedef struct{

    uint32_t blksize, flags;

    int rate, chan, bpp;

    uint32_t samples, soff;

    int block_parsed;

    uint8_t extra[WV_EXTRA_SIZE];

    int64_t pos;

}WVContext;

static int wv_probe(AVProbeData *p)

{

    /* check file header */

    if (p->buf_size <= 32)

        return 0;

    if (p->buf[0] == 'w' && p->buf[1] == 'v' &&

        p->buf[2] == 'p' && p->buf[3] == 'k')

        return AVPROBE_SCORE_MAX;

    else

        return 0;

}

static int wv_read_block_header(AVFormatContext *ctx, ByteIOContext *pb)

{

    WVContext *wc = ctx->priv_data;

    uint32_t tag, ver;

    int size;

    int rate, bpp, chan;

    wc->pos = url_ftell(pb);

    tag = get_le32(pb);

    if (tag != MKTAG('w', 'v', 'p', 'k'))

        return -1;

    size = get_le32(pb);

    if(size < 24 || size > WV_BLOCK_LIMIT){

        av_log(ctx, AV_LOG_ERROR, "Incorrect block size %i\n", size);

        return -1;

    }

    wc->blksize = size;

    ver = get_le16(pb);

    if(ver < 0x402 || ver > 0x410){

        av_log(ctx, AV_LOG_ERROR, "Unsupported version %03X\n", ver);

        return -1;

    }

    get_byte(pb); // track no

    get_byte(pb); // track sub index

    wc->samples = get_le32(pb); // total samples in file

    wc->soff = get_le32(pb); // offset in samples of current block

    get_buffer(pb, wc->extra, WV_EXTRA_SIZE);

    wc->flags = AV_RL32(wc->extra + 4);

    //parse flags

    if(wc->flags & WV_FLOAT){

        av_log(ctx, AV_LOG_ERROR, "Floating point data is not supported\n");

        return -1;

    }

    if(wc->flags & WV_HYBRID){

        av_log(ctx, AV_LOG_ERROR, "Hybrid coding mode is not supported\n");

        return -1;

    }

    bpp = ((wc->flags & 3) + 1) << 3;

    chan = 1 + !(wc->flags & WV_MONO);

    rate = wv_rates[(wc->flags >> 23) & 0xF];

    if(rate == -1){

        av_log(ctx, AV_LOG_ERROR, "Unknown sampling rate\n");

        return -1;

    }

    if(!wc->bpp) wc->bpp = bpp;

    if(!wc->chan) wc->chan = chan;

    if(!wc->rate) wc->rate = rate;

    if(wc->flags && bpp != wc->bpp){

        av_log(ctx, AV_LOG_ERROR, "Bits per sample differ, this block: %i, header block: %i\n", bpp, wc->bpp);

        return -1;

    }

    if(wc->flags && chan != wc->chan){

        av_log(ctx, AV_LOG_ERROR, "Channels differ, this block: %i, header block: %i\n", chan, wc->chan);

        return -1;

    }

    if(wc->flags && rate != wc->rate){

        av_log(ctx, AV_LOG_ERROR, "Sampling rate differ, this block: %i, header block: %i\n", rate, wc->rate);

        return -1;

    }

    wc->blksize = size - 24;

    return 0;

}

static int wv_read_header(AVFormatContext *s,

                          AVFormatParameters *ap)

{

    ByteIOContext *pb = s->pb;

    WVContext *wc = s->priv_data;

    AVStream *st;

    if(wv_read_block_header(s, pb) < 0)

        return -1;

    wc->block_parsed = 0;

    /* now we are ready: build format streams */

    st = av_new_stream(s, 0);

    if (!st)

        return -1;

    st->codec->codec_type = CODEC_TYPE_AUDIO;

    st->codec->codec_id = CODEC_ID_WAVPACK;

    st->codec->channels = wc->chan;

    st->codec->sample_rate = wc->rate;

    st->codec->bits_per_coded_sample = wc->bpp;

    av_set_pts_info(st, 64, 1, wc->rate);

    s->start_time = 0;

    s->duration = (int64_t)wc->samples * AV_TIME_BASE / st->codec->sample_rate;

    return 0;

}

static int wv_read_packet(AVFormatContext *s,

                          AVPacket *pkt)

{

    WVContext *wc = s->priv_data;

    int ret;

    if (url_feof(s->pb))

        return AVERROR(EIO);

    if(wc->block_parsed){

        if(wv_read_block_header(s, s->pb) < 0)

            return -1;

    }

    if(av_new_packet(pkt, wc->blksize + WV_EXTRA_SIZE) < 0)

        return AVERROR(ENOMEM);

    memcpy(pkt->data, wc->extra, WV_EXTRA_SIZE);

    ret = get_buffer(s->pb, pkt->data + WV_EXTRA_SIZE, wc->blksize);

    if(ret != wc->blksize){

        av_free_packet(pkt);

        return AVERROR(EIO);

    }

    pkt->stream_index = 0;

    wc->block_parsed = 1;

    pkt->size = ret + WV_EXTRA_SIZE;

    pkt->pts = wc->soff;

    av_add_index_entry(s->streams[0], wc->pos, pkt->pts, 0, 0, AVINDEX_KEYFRAME);

    return 0;

}

static int wv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)

{

    AVStream *st = s->streams[stream_index];

    WVContext *wc = s->priv_data;

    AVPacket pkt1, *pkt = &pkt1;

    int ret;

    int index = av_index_search_timestamp(st, timestamp, flags);

    int64_t pos, pts;

    /* if found, seek there */

    if (index >= 0){

        wc->block_parsed = 1;

        url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET);

        return 0;

    }

    /* if timestamp is out of bounds, return error */

    if(timestamp < 0 || timestamp >= s->duration)

        return -1;

    pos = url_ftell(s->pb);

    do{

        ret = av_read_frame(s, pkt);

        if (ret < 0){

            url_fseek(s->pb, pos, SEEK_SET);

            return -1;

        }

        pts = pkt->pts;

        av_free_packet(pkt);

    }while(pts < timestamp);

    return 0;

}

AVInputFormat wv_demuxer = {

    "wv",

    NULL_IF_CONFIG_SMALL("WavPack"),

    sizeof(WVContext),

    wv_probe,

    wv_read_header,

    wv_read_packet,

    NULL,

    wv_read_seek,

};