/*

 * Vividas VIV format Demuxer

 * Copyright (c) 2012 Krzysztof Klinikowski

 * Copyright (c) 2010 Andrzej Szombierski

 * based on vivparse Copyright (c) 2007 Måns Rullgård

 *

 * 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

 */

/**

 * @file

 * @brief Vividas VIV (.viv) file demuxer

 * @author Andrzej Szombierski [qq at kuku eu org] (2010-07)

 * @sa http://wiki.multimedia.cx/index.php?title=Vividas_VIV

 */

#include "libavutil/avassert.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/mem.h"

#include "avio_internal.h"

#include "avformat.h"

#include "demux.h"

#include "internal.h"

#define MAX_AUDIO_SUBPACKETS 100

typedef struct VIV_SB_block {

    int size, n_packets;

    int64_t byte_offset;

    int64_t packet_offset;

} VIV_SB_block;

typedef struct VIV_SB_entry {

    int size, flag;

} VIV_SB_entry;

typedef struct VIV_AudioSubpacket {

    int start, pcm_bytes;

} VIV_AudioSubpacket;

typedef struct VividasDemuxContext {

    int n_sb_blocks;

    VIV_SB_block *sb_blocks;

    int num_audio;

    uint32_t sb_key;

    int64_t sb_offset;

    int current_sb, current_sb_entry;

    uint8_t *sb_buf;

    AVIOContext *sb_pb;

    int n_sb_entries;

    VIV_SB_entry *sb_entries;

    int n_audio_subpackets;

    int current_audio_subpacket;

    int64_t audio_sample;

    VIV_AudioSubpacket audio_subpackets[MAX_AUDIO_SUBPACKETS];

} VividasDemuxContext;

static int viv_probe(const AVProbeData *p)

{

    if (memcmp(p->buf, "vividas03", 9))

        return 0;

    return AVPROBE_SCORE_MAX;

}

static const uint8_t keybits[32] = {

 20,  52, 111,  10,  27,  71, 142,  53,

 82, 138,   1,  78,  86, 121, 183,  85,

105, 152,  39, 140, 172,  11,  64, 144,

155,   6,  71, 163, 186,  49, 126,  43,

};

static uint32_t decode_key(uint8_t *buf)

{

    uint32_t key = 0;

    for (int i = 0; i < 32; i++) {

        unsigned p = keybits[i];

        key |= ((buf[p] >> ((i*5+3)&7)) & 1u) << i;

    }

    return key;

}

static void put_v(uint8_t *p, unsigned v)

{

    if (v>>28)

        *p++ = ((v>>28)&0x7f)|0x80;

    if (v>>21)

        *p++ = ((v>>21)&0x7f)|0x80;

    if (v>>14)

        *p++ = ((v>>14)&0x7f)|0x80;

    if (v>>7)

        *p++ =  ((v>>7)&0x7f)|0x80;

}

static unsigned recover_key(unsigned char sample[4], unsigned expected_size)

{

    unsigned char plaintext[8] = { 'S', 'B' };

    put_v(plaintext+2, expected_size);

    return AV_RL32(sample) ^ AV_RL32(plaintext);

}

static void xor_block(void *p1, void *p2, unsigned size, int key, unsigned *key_ptr)

{

    unsigned *d1 = p1;

    unsigned *d2 = p2;

    unsigned k = *key_ptr;

    size >>= 2;

    while (size > 0) {

        *d2 = *d1 ^ (HAVE_BIGENDIAN ? av_bswap32(k) : k);

        k += key;

        d1++;

        d2++;

        size--;

    }

    *key_ptr = k;

}

static void decode_block(uint8_t *src, uint8_t *dest, unsigned size,

                         uint32_t key, uint32_t *key_ptr,

                         int align)

{

    unsigned s = size;

    char tmp[4];

    int a2;

    if (!size)

        return;

    align &= 3;

    a2 = (4 - align) & 3;

    if (align) {

        uint32_t tmpkey = *key_ptr - key;

        if (a2 > s) {

            a2 = s;

            avpriv_request_sample(NULL, "tiny aligned block");

        }

        memcpy(tmp + align, src, a2);

        xor_block(tmp, tmp, 4, key, &tmpkey);

        memcpy(dest, tmp + align, a2);

        s -= a2;

    }

    if (s >= 4) {

        xor_block(src + a2, dest + a2, s & ~3,

                  key, key_ptr);

        s &= 3;

    }

    if (s) {

        size -= s;

        memcpy(tmp, src + size, s);

        xor_block(&tmp, &tmp, 4, key, key_ptr);

        memcpy(dest + size, tmp, s);

    }

}

static uint32_t get_v(uint8_t *p, int len)

{

    uint32_t v = 0;

    const uint8_t *end = p + len;

    do {

        if (p >= end || v >= UINT_MAX / 128 - *p)

            return v;

        v <<= 7;

        v += *p & 0x7f;

    } while (*p++ & 0x80);

    return v;

}

static uint8_t *read_vblock(AVIOContext *src, uint32_t *size,

                            uint32_t key, uint32_t *k2, int align)

{

    uint8_t tmp[4];

    uint8_t *buf;

    unsigned n;

    if (avio_read(src, tmp, 4) != 4)

        return NULL;

    decode_block(tmp, tmp, 4, key, k2, align);

    n = get_v(tmp, 4);

    if (n < 4)

        return NULL;

    buf = av_malloc(n);

    if (!buf)

        return NULL;

    *size = n;

    n -= 4;

    memcpy(buf, tmp, 4);

    if (avio_read(src, buf + 4, n) == n) {

        decode_block(buf + 4, buf + 4, n, key, k2, align);

    } else {

        av_free(buf);

        buf = NULL;

    }

    return buf;

}

static uint8_t *read_sb_block(AVIOContext *src, unsigned *size,

                              uint32_t *key, unsigned expected_size)

{

    uint8_t *buf;

    uint8_t ibuf[8], sbuf[8];

    uint32_t k2;

    unsigned n;

    if (avio_read(src, ibuf, 8) < 8)

        return NULL;

    k2 = *key;

    decode_block(ibuf, sbuf, 8, *key, &k2, 0);

    n = get_v(sbuf+2, 6);

    if (sbuf[0] != 'S' || sbuf[1] != 'B' || (expected_size>0 && n != expected_size)) {

        uint32_t tmpkey = recover_key(ibuf, expected_size);

        k2 = tmpkey;

        decode_block(ibuf, sbuf, 8, tmpkey, &k2, 0);

        n = get_v(sbuf+2, 6);

        if (sbuf[0] != 'S' || sbuf[1] != 'B' || expected_size != n)

            return NULL;

        *key = tmpkey;

    }

    if (n < 8)

        return NULL;

    buf = av_malloc(n);

    if (!buf)

        return NULL;

    memcpy(buf, sbuf, 8);

    *size = n;

    n -= 8;

    if (avio_read(src, buf+8, n) != n) {

        av_free(buf);

        return NULL;

    }

    decode_block(buf + 8, buf + 8, n, *key, &k2, 0);

    return buf;

}

static int track_header(VividasDemuxContext *viv, AVFormatContext *s,

                        const uint8_t *buf, int size)

{

    int i, j, ret;

    int64_t off;

    int val_1;

    int num_video;

    FFIOContext pb0;

    AVIOContext *const pb = &pb0.pub;

    ffio_init_read_context(&pb0, buf, size);

    ffio_read_varlen(pb); // track_header_len

    avio_r8(pb); // '1'

    val_1 = ffio_read_varlen(pb);

    for (i=0;i<val_1;i++) {

        int c = avio_r8(pb);

        if (avio_feof(pb))

            return AVERROR_EOF;

        for (j=0;j<c;j++) {

            if (avio_feof(pb))

                return AVERROR_EOF;

            avio_r8(pb); // val_3

            avio_r8(pb); // val_4

        }

    }

    avio_r8(pb); // num_streams

    off = avio_tell(pb);

    off += ffio_read_varlen(pb); // val_5

    avio_r8(pb); // '2'

    num_video = avio_r8(pb);

    avio_seek(pb, off, SEEK_SET);

    if (num_video != 1) {

        av_log(s, AV_LOG_ERROR, "number of video tracks %d is not 1\n", num_video);

        return AVERROR_PATCHWELCOME;

    }

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

        AVStream *st = avformat_new_stream(s, NULL);

        int num, den;

        if (!st)

            return AVERROR(ENOMEM);

        st->id = i;

        st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

        st->codecpar->codec_id = AV_CODEC_ID_VP6;

        off = avio_tell(pb);

        off += ffio_read_varlen(pb);

        avio_r8(pb); // '3'

        avio_r8(pb); // val_7

        num = avio_rl32(pb); // frame_time

        den = avio_rl32(pb); // time_base

        avpriv_set_pts_info(st, 64, num, den);

        st->nb_frames = avio_rl32(pb); // n frames

        st->codecpar->width = avio_rl16(pb); // width

        st->codecpar->height = avio_rl16(pb); // height

        avio_r8(pb); // val_8

        avio_rl32(pb); // val_9

        avio_seek(pb, off, SEEK_SET);

    }

    off = avio_tell(pb);

    off += ffio_read_varlen(pb); // val_10

    avio_r8(pb); // '4'

    viv->num_audio = avio_r8(pb);

    avio_seek(pb, off, SEEK_SET);

    if (viv->num_audio != 1)

        av_log(s, AV_LOG_WARNING, "number of audio tracks %d is not 1\n", viv->num_audio);

    for(i=0;i<viv->num_audio;i++) {

        int q;

        AVStream *st = avformat_new_stream(s, NULL);

        if (!st)

            return AVERROR(ENOMEM);

        st->id = num_video + i;

        st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codecpar->codec_id = AV_CODEC_ID_VORBIS;

        off = avio_tell(pb);

        off += ffio_read_varlen(pb); // length

        avio_r8(pb); // '5'

        avio_r8(pb); //codec_id

        avio_rl16(pb); //codec_subid

        st->codecpar->ch_layout.nb_channels = avio_rl16(pb); // channels

        st->codecpar->sample_rate = avio_rl32(pb); // sample_rate

        if (st->codecpar->sample_rate <= 0 || st->codecpar->ch_layout.nb_channels <= 0)

            return AVERROR_INVALIDDATA;

        avio_seek(pb, 10, SEEK_CUR); // data_1

        q = avio_r8(pb);

        avio_seek(pb, q, SEEK_CUR); // data_2

        avio_r8(pb); // zeropad

        if (avio_tell(pb) < off) {

            int num_data;

            int xd_size = 1;

            int data_len[256];

            int offset = 1;

            uint8_t *p;

            ffio_read_varlen(pb); // val_13

            avio_r8(pb); // '19'

            ffio_read_varlen(pb); // len_3

            num_data = avio_r8(pb);

            for (j = 0; j < num_data; j++) {

                int64_t len = ffio_read_varlen(pb);

                if (len < 0 || len > INT_MAX/2 - xd_size) {

                    return AVERROR_INVALIDDATA;

                }

                data_len[j] = len;

                xd_size += len + 1 + len/255;

            }

            ret = ff_alloc_extradata(st->codecpar, xd_size);

            if (ret < 0)

                return ret;

            p = st->codecpar->extradata;

            p[0] = 2;

            for (j = 0; j < num_data - 1; j++) {

                unsigned delta = av_xiphlacing(&p[offset], data_len[j]);

                av_assert0(delta <= xd_size - offset);

                offset += delta;

            }

            for (j = 0; j < num_data; j++) {

                int ret = avio_read(pb, &p[offset], data_len[j]);

                if (ret < data_len[j]) {

                    st->codecpar->extradata_size = 0;

                    av_freep(&st->codecpar->extradata);

                    break;

                }

                av_assert0(data_len[j] <= xd_size - offset);

                offset += data_len[j];

            }

            if (offset < st->codecpar->extradata_size)

                st->codecpar->extradata_size = offset;

        }

    }

    return 0;

}

static int track_index(VividasDemuxContext *viv, AVFormatContext *s,

                       const uint8_t *buf, unsigned size)

{

    int64_t off;

    int64_t poff;

    int maxnp=0;

    FFIOContext pb0;

    AVIOContext *const pb = &pb0.pub;

    int i;

    int64_t filesize = avio_size(s->pb);

    uint64_t n_sb_blocks_tmp;

    ffio_init_read_context(&pb0, buf, size);

    ffio_read_varlen(pb); // track_index_len

    avio_r8(pb); // 'c'

    n_sb_blocks_tmp = ffio_read_varlen(pb);

    if (n_sb_blocks_tmp > size / 2)

        return AVERROR_INVALIDDATA;

    viv->sb_blocks = av_calloc(n_sb_blocks_tmp, sizeof(*viv->sb_blocks));

    if (!viv->sb_blocks) {

        return AVERROR(ENOMEM);

    }

    viv->n_sb_blocks = n_sb_blocks_tmp;

    off = 0;

    poff = 0;

    for (i = 0; i < viv->n_sb_blocks; i++) {

        uint64_t size_tmp      = ffio_read_varlen(pb);

        uint64_t n_packets_tmp = ffio_read_varlen(pb);

        if (size_tmp > INT_MAX || n_packets_tmp > INT_MAX)

            return AVERROR_INVALIDDATA;

        viv->sb_blocks[i].byte_offset = off;

        viv->sb_blocks[i].packet_offset = poff;

        viv->sb_blocks[i].size = size_tmp;

        viv->sb_blocks[i].n_packets = n_packets_tmp;

        off += viv->sb_blocks[i].size;

        poff += viv->sb_blocks[i].n_packets;

        if (maxnp < viv->sb_blocks[i].n_packets)

            maxnp = viv->sb_blocks[i].n_packets;

    }

    if (filesize > 0 && poff > filesize)

        return AVERROR_INVALIDDATA;

    viv->sb_entries = av_calloc(maxnp, sizeof(VIV_SB_entry));

    if (!viv->sb_entries)

        return AVERROR(ENOMEM);

    return 0;

}

static void load_sb_block(AVFormatContext *s, VividasDemuxContext *viv, unsigned expected_size)

{

    uint32_t size = 0;

    int i;

    AVIOContext *pb = 0;

    if (viv->sb_pb) {

        av_free(viv->sb_pb);

        viv->sb_pb = NULL;

    }

    if (viv->sb_buf)

        av_free(viv->sb_buf);

    viv->sb_buf = read_sb_block(s->pb, &size, &viv->sb_key, expected_size);

    if (!viv->sb_buf) {

        return;

    }

    pb = avio_alloc_context(viv->sb_buf, size, 0, NULL, NULL, NULL, NULL);

    if (!pb)

        return;

    viv->sb_pb = pb;

    avio_r8(pb); //  'S'

    avio_r8(pb); //  'B'

    ffio_read_varlen(pb); //  size

    avio_r8(pb); //  junk

    ffio_read_varlen(pb); // first packet

    viv->n_sb_entries = viv->sb_blocks[viv->current_sb].n_packets;

    for (i = 0; i < viv->n_sb_entries; i++) {

        viv->sb_entries[i].size = ffio_read_varlen(pb);

        viv->sb_entries[i].flag = avio_r8(pb);

    }

    ffio_read_varlen(pb);

    avio_r8(pb);

    viv->current_sb_entry = 0;

}

static int viv_read_header(AVFormatContext *s)

{

    VividasDemuxContext *viv = s->priv_data;

    AVIOContext *pb = s->pb;

    int64_t header_end;

    int num_tracks;

    uint32_t key, k2;

    uint32_t v;

    uint8_t keybuffer[187];

    uint32_t b22_size = 0;

    uint32_t b22_key = 0;

    uint8_t *buf = 0;

    int ret;

    avio_skip(pb, 9);

    header_end = avio_tell(pb);

    header_end += ffio_read_varlen(pb);

    num_tracks = avio_r8(pb);

    if (num_tracks != 1) {

        av_log(s, AV_LOG_ERROR, "number of tracks %d is not 1\n", num_tracks);

        return AVERROR(EINVAL);

    }

    v = avio_r8(pb);

    avio_seek(pb, v, SEEK_CUR);

    ret = ffio_read_size(pb, keybuffer, 187);

    if (ret < 0)

        return ret;

    key = decode_key(keybuffer);

    viv->sb_key = key;

    avio_rl32(pb);

    for (;;) {

        int64_t here = avio_tell(pb);

        int block_len, block_type;

        if (here >= header_end)

            break;

        block_len = ffio_read_varlen(pb);

        if (avio_feof(pb) || block_len <= 0)

            return AVERROR_INVALIDDATA;

        block_type = avio_r8(pb);

        if (block_type == 22) {

            avio_read(pb, keybuffer, 187);

            b22_key = decode_key(keybuffer);

            b22_size = avio_rl32(pb);

        }

        avio_seek(pb, here + block_len, SEEK_SET);

    }

    if (b22_size) {

        k2 = b22_key;

        buf = read_vblock(pb, &v, b22_key, &k2, 0);

        if (!buf)

            return AVERROR_INVALIDDATA;

        av_free(buf);

    }

    k2 = key;

    buf = read_vblock(pb, &v, key, &k2, 0);

    if (!buf)

        return AVERROR_INVALIDDATA;

    ret = track_header(viv, s, buf, v);

    av_free(buf);

    if (ret < 0)

        return ret;

    buf = read_vblock(pb, &v, key, &k2, v);

    if (!buf)

        return AVERROR_INVALIDDATA;

    ret = track_index(viv, s, buf, v);

    av_free(buf);

    if (ret < 0)

        return ret;

    viv->sb_offset = avio_tell(pb);

    if (viv->n_sb_blocks > 0) {

        viv->current_sb = 0;

        load_sb_block(s, viv, viv->sb_blocks[0].size);

    } else {

        viv->current_sb = -1;

    }

    return 0;

}

static int viv_read_packet(AVFormatContext *s,

                           AVPacket *pkt)

{

    VividasDemuxContext *viv = s->priv_data;

    AVIOContext *pb;

    int64_t off;

    int ret;

    if (!viv->sb_pb)

        return AVERROR_INVALIDDATA;

    if (avio_feof(viv->sb_pb))

        return AVERROR_EOF;

    if (viv->current_audio_subpacket < viv->n_audio_subpackets) {

        AVStream *astream;

        int size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - viv->audio_subpackets[viv->current_audio_subpacket].start;

        pb = viv->sb_pb;

        ret = av_get_packet(pb, pkt, size);

        if (ret < 0)

            return ret;

        pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;

        pkt->stream_index = 1;

        astream = s->streams[pkt->stream_index];

        pkt->pts = av_rescale_q(viv->audio_sample, av_make_q(1, astream->codecpar->sample_rate), astream->time_base);

        viv->audio_sample += viv->audio_subpackets[viv->current_audio_subpacket].pcm_bytes / 2 /

                             astream->codecpar->ch_layout.nb_channels;

        pkt->flags |= AV_PKT_FLAG_KEY;

        viv->current_audio_subpacket++;

        return 0;

    }

    if (viv->current_sb_entry >= viv->n_sb_entries) {

        if (viv->current_sb+1 >= viv->n_sb_blocks)

            return AVERROR_INVALIDDATA;

        viv->current_sb++;

        load_sb_block(s, viv, 0);

        viv->current_sb_entry = 0;

    }

    pb = viv->sb_pb;

    if (!pb)

        return AVERROR_INVALIDDATA;

    off = avio_tell(pb);

    if (viv->current_sb_entry >= viv->n_sb_entries)

        return AVERROR_INVALIDDATA;

    off += viv->sb_entries[viv->current_sb_entry].size;

    if (viv->sb_entries[viv->current_sb_entry].flag == 0) {

        uint64_t v_size = ffio_read_varlen(pb);

        int last = 0, last_start;

        if (!viv->num_audio)

            return AVERROR_INVALIDDATA;

        ffio_read_varlen(pb);

        if (v_size > INT_MAX || !v_size)

            return AVERROR_INVALIDDATA;

        ret = av_get_packet(pb, pkt, v_size);

        if (ret < 0)

            return ret;

        pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;

        pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;

        pkt->flags |= (pkt->data[0]&0x80)?0:AV_PKT_FLAG_KEY;

        pkt->stream_index = 0;

        for (int i = 0; i < MAX_AUDIO_SUBPACKETS - 1; i++) {

            int start, pcm_bytes;

            start = ffio_read_varlen(pb);

            pcm_bytes = ffio_read_varlen(pb);

            if (i > 0 && start == 0)

                break;

            if (start < last)

                return AVERROR_INVALIDDATA;

            viv->n_audio_subpackets = i + 1;

            last =

            viv->audio_subpackets[i].start = start;

            viv->audio_subpackets[i].pcm_bytes = pcm_bytes;

        }

        last_start =

        viv->audio_subpackets[viv->n_audio_subpackets].start = (int)(off - avio_tell(pb));

        if (last_start < last)

            return AVERROR_INVALIDDATA;

        viv->current_audio_subpacket = 0;

    } else {

        uint64_t v_size = ffio_read_varlen(pb);

        if (v_size > INT_MAX || !v_size)

            return AVERROR_INVALIDDATA;

        ret = av_get_packet(pb, pkt, v_size);

        if (ret < 0)

            return ret;

        pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;

        pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;

        pkt->flags |= (pkt->data[0] & 0x80) ? 0 : AV_PKT_FLAG_KEY;

        pkt->stream_index = 0;

    }

    viv->current_sb_entry++;

    return 0;

}

static int viv_read_close(AVFormatContext *s)

{

    VividasDemuxContext *viv = s->priv_data;

    av_freep(&viv->sb_pb);

    av_freep(&viv->sb_buf);

    av_freep(&viv->sb_blocks);

    av_freep(&viv->sb_entries);

    return 0;

}

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

{

    VividasDemuxContext *viv = s->priv_data;

    int64_t frame;

    if (stream_index == 0)

        frame = timestamp;

    else

        frame = av_rescale_q(timestamp, s->streams[0]->time_base, s->streams[stream_index]->time_base);

    for (int i = 0; i < viv->n_sb_blocks; i++) {

        if (frame >= viv->sb_blocks[i].packet_offset && frame < viv->sb_blocks[i].packet_offset + viv->sb_blocks[i].n_packets) {

            viv->current_sb = i;

            // seek to ith sb block

            avio_seek(s->pb, viv->sb_offset + viv->sb_blocks[i].byte_offset, SEEK_SET);

            // load the block

            load_sb_block(s, viv, 0);

            if (viv->num_audio) {

                const AVCodecParameters *par = s->streams[1]->codecpar;

                // flush audio packet queue

                viv->current_audio_subpacket = 0;

                viv->n_audio_subpackets      = 0;

                // most problematic part: guess audio offset

                viv->audio_sample = av_rescale_q(viv->sb_blocks[i].packet_offset,

                                                 av_make_q(par->sample_rate, 1),

                                                 av_inv_q(s->streams[0]->time_base));

                // hand-tuned 1.s a/v offset

                viv->audio_sample += par->sample_rate;

            }

            viv->current_sb_entry = 0;

            return 1;

        }

    }

    return 0;

}

const FFInputFormat ff_vividas_demuxer = {

    .p.name         = "vividas",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Vividas VIV"),

    .priv_data_size = sizeof(VividasDemuxContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = viv_probe,

    .read_header    = viv_read_header,

    .read_packet    = viv_read_packet,

    .read_close     = viv_read_close,

    .read_seek      = viv_read_seek,

};