/*

 * Magic Lantern Video (MLV) demuxer

 * Copyright (c) 2014 Peter Ross

 *

 * 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

 * Magic Lantern Video (MLV) demuxer

 */

#include <time.h>

#include "libavcodec/bytestream.h"

#include "libavcodec/tiff.h"

#include "libavcodec/tiff_common.h"

#include "libavutil/imgutils.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/mem.h"

#include "libavutil/rational.h"

#include "avformat.h"

#include "demux.h"

#include "internal.h"

#include "riff.h"

#define MLV_VERSION "v2.0"

#define MLV_VIDEO_CLASS_RAW  1

#define MLV_VIDEO_CLASS_YUV  2

#define MLV_VIDEO_CLASS_JPEG 3

#define MLV_VIDEO_CLASS_H264 4

#define MLV_AUDIO_CLASS_WAV  1

#define MLV_CLASS_FLAG_LJ92  0x20

#define MLV_CLASS_FLAG_DELTA 0x40

#define MLV_CLASS_FLAG_LZMA  0x80

typedef struct {

    AVIOContext *pb[101];

    int class[2];

    int stream_index;

    uint64_t pts;

    int black_level;

    int white_level;

    int color_matrix1[9][2];

} MlvContext;

static int probe(const AVProbeData *p)

{

    if (AV_RL32(p->buf) == MKTAG('M','L','V','I') &&

        AV_RL32(p->buf + 4) >= 52 &&

        !memcmp(p->buf + 8, MLV_VERSION, 5))

        return AVPROBE_SCORE_MAX;

    return 0;

}

static int check_file_header(AVIOContext *pb, uint64_t guid)

{

    unsigned int size;

    uint8_t version[8];

    avio_skip(pb, 4);

    size = avio_rl32(pb);

    if (size < 52)

        return AVERROR_INVALIDDATA;

    avio_read(pb, version, 8);

    if (memcmp(version, MLV_VERSION, 5) || avio_rl64(pb) != guid)

        return AVERROR_INVALIDDATA;

    avio_skip(pb, size - 24);

    return 0;

}

static void read_string(AVFormatContext *avctx, AVIOContext *pb, const char *tag, unsigned size)

{

    char * value = av_malloc(size + 1);

    int ret;

    if (!value) {

        avio_skip(pb, size);

        return;

    }

    ret = avio_read(pb, value, size);

    if (ret != size || !value[0]) {

        av_free(value);

        return;

    }

    value[size] = 0;

    av_dict_set(&avctx->metadata, tag, value, AV_DICT_DONT_STRDUP_VAL);

}

static void read_uint8(AVFormatContext *avctx, AVIOContext *pb, const char *tag, const char *fmt)

{

    av_dict_set_int(&avctx->metadata, tag, avio_r8(pb), 0);

}

static void read_uint16(AVFormatContext *avctx, AVIOContext *pb, const char *tag, const char *fmt)

{

    av_dict_set_int(&avctx->metadata, tag, avio_rl16(pb), 0);

}

static void read_uint32(AVFormatContext *avctx, AVIOContext *pb, const char *tag, const char *fmt)

{

    av_dict_set_int(&avctx->metadata, tag, avio_rl32(pb), 0);

}

static void read_uint64(AVFormatContext *avctx, AVIOContext *pb, const char *tag, const char *fmt)

{

    av_dict_set_int(&avctx->metadata, tag, avio_rl64(pb), 0);

}

static int scan_file(AVFormatContext *avctx, AVStream *vst, AVStream *ast, int file)

{

    FFStream *const vsti = ffstream(vst), *const asti = ffstream(ast);

    MlvContext *mlv = avctx->priv_data;

    AVIOContext *pb = mlv->pb[file];

    int ret;

    while (!avio_feof(pb)) {

        int type;

        unsigned int size;

        type = avio_rl32(pb);

        size = avio_rl32(pb);

        avio_skip(pb, 8); //timestamp

        if (size < 16)

            break;

        size -= 16;

        if (vst && type == MKTAG('R','A','W','I') && size >= 164) {

            unsigned width  = avio_rl16(pb);

            unsigned height = avio_rl16(pb);

            unsigned bits_per_coded_sample;

            ret = av_image_check_size(width, height, 0, avctx);

            if (ret < 0)

                return ret;

            if (avio_rl32(pb) != 1)

                avpriv_request_sample(avctx, "raw api version");

            avio_skip(pb, 20); // pointer, width, height, pitch, frame_size

            bits_per_coded_sample = avio_rl32(pb);

            if (bits_per_coded_sample > (INT_MAX - 7) / (width * height)) {

                av_log(avctx, AV_LOG_ERROR,

                       "invalid bits_per_coded_sample %u (size: %ux%u)\n",

                       bits_per_coded_sample, width, height);

                return AVERROR_INVALIDDATA;

            }

            vst->codecpar->width  = width;

            vst->codecpar->height = height;

            vst->codecpar->bits_per_coded_sample = bits_per_coded_sample;

            mlv->black_level = avio_rl32(pb);

            mlv->white_level = avio_rl32(pb);

            avio_skip(pb, 16 + 24); // xywh, active_area, exposure_bias

            if (avio_rl32(pb) != 0x2010100) /* RGGB */

                avpriv_request_sample(avctx, "cfa_pattern");

            avio_skip(pb, 4); // calibration_illuminant1,

            for (int i = 0; i < 9; i++) {

                mlv->color_matrix1[i][0] = avio_rl32(pb);

                mlv->color_matrix1[i][1] = avio_rl32(pb);

            }

            avio_skip(pb, 4); // dynamic_range

            vst->codecpar->format    = AV_PIX_FMT_BAYER_RGGB16LE;

            vst->codecpar->codec_tag = MKTAG('B', 'I', 'T', 16);

            size -= 164;

        } else if (ast && type == MKTAG('W', 'A', 'V', 'I') && size >= 16) {

            ret = ff_get_wav_header(avctx, pb, ast->codecpar, 16, 0);

            if (ret < 0)

                return ret;

            size -= 16;

        } else if (type == MKTAG('I','N','F','O')) {

            if (size > 0)

                read_string(avctx, pb, "info", size);

            continue;

        } else if (type == MKTAG('I','D','N','T') && size >= 36) {

            read_string(avctx, pb, "cameraName", 32);

            read_uint32(avctx, pb, "cameraModel", "0x%"PRIx32);

            size -= 36;

            if (size >= 32) {

                read_string(avctx, pb, "cameraSerial", 32);

                size -= 32;

            }

        } else if (type == MKTAG('L','E','N','S') && size >= 48) {

            read_uint16(avctx, pb, "focalLength", "%i");

            read_uint16(avctx, pb, "focalDist", "%i");

            read_uint16(avctx, pb, "aperture", "%i");

            read_uint8(avctx, pb, "stabilizerMode", "%i");

            read_uint8(avctx, pb, "autofocusMode", "%i");

            read_uint32(avctx, pb, "flags", "0x%"PRIx32);

            read_uint32(avctx, pb, "lensID", "%"PRIi32);

            read_string(avctx, pb, "lensName", 32);

            size -= 48;

            if (size >= 32) {

                read_string(avctx, pb, "lensSerial", 32);

                size -= 32;

            }

        } else if (vst && type == MKTAG('V', 'I', 'D', 'F') && size >= 4) {

            uint64_t pts = avio_rl32(pb);

            ff_add_index_entry(&vsti->index_entries, &vsti->nb_index_entries,

                               &vsti->index_entries_allocated_size,

                               avio_tell(pb) - 20, pts, file, 0, AVINDEX_KEYFRAME);

            size -= 4;

        } else if (ast && type == MKTAG('A', 'U', 'D', 'F') && size >= 4) {

            uint64_t pts = avio_rl32(pb);

            ff_add_index_entry(&asti->index_entries, &asti->nb_index_entries,

                               &asti->index_entries_allocated_size,

                               avio_tell(pb) - 20, pts, file, 0, AVINDEX_KEYFRAME);

            size -= 4;

        } else if (vst && type == MKTAG('W','B','A','L') && size >= 28) {

            read_uint32(avctx, pb, "wb_mode", "%"PRIi32);

            read_uint32(avctx, pb, "kelvin", "%"PRIi32);

            read_uint32(avctx, pb, "wbgain_r", "%"PRIi32);

            read_uint32(avctx, pb, "wbgain_g", "%"PRIi32);

            read_uint32(avctx, pb, "wbgain_b", "%"PRIi32);

            read_uint32(avctx, pb, "wbs_gm", "%"PRIi32);

            read_uint32(avctx, pb, "wbs_ba", "%"PRIi32);

            size -= 28;

        } else if (type == MKTAG('R','T','C','I') && size >= 20) {

            char str[32];

            struct tm time = { 0 };

            time.tm_sec    = avio_rl16(pb);

            time.tm_min    = avio_rl16(pb);

            time.tm_hour   = avio_rl16(pb);

            time.tm_mday   = avio_rl16(pb);

            time.tm_mon    = avio_rl16(pb);

            time.tm_year   = avio_rl16(pb);

            time.tm_wday   = avio_rl16(pb);

            time.tm_yday   = avio_rl16(pb);

            time.tm_isdst  = avio_rl16(pb);

            avio_skip(pb, 2);

            if (strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", &time))

                av_dict_set(&avctx->metadata, "time", str, 0);

            size -= 20;

        } else if (type == MKTAG('E','X','P','O') && size >= 16) {

            av_dict_set(&avctx->metadata, "isoMode", avio_rl32(pb) ? "auto" : "manual", 0);

            read_uint32(avctx, pb, "isoValue", "%"PRIi32);

            read_uint32(avctx, pb, "isoAnalog", "%"PRIi32);

            read_uint32(avctx, pb, "digitalGain", "%"PRIi32);

            size -= 16;

            if (size >= 8) {

                read_uint64(avctx, pb, "shutterValue", "%"PRIi64);

                size -= 8;

            }

        } else if (type == MKTAG('S','T','Y','L') && size >= 36) {

            read_uint32(avctx, pb, "picStyleId", "%"PRIi32);

            read_uint32(avctx, pb, "contrast", "%"PRIi32);

            read_uint32(avctx, pb, "sharpness", "%"PRIi32);

            read_uint32(avctx, pb, "saturation", "%"PRIi32);

            read_uint32(avctx, pb, "colortone", "%"PRIi32);

            read_string(avctx, pb, "picStyleName", 16);

            size -= 36;

        } else if (type == MKTAG('V','E','R','S') && size >= 4) {

            unsigned int length = avio_rl32(pb);

            read_string(avctx, pb, "version", length);

            size -= length + 4;

        } else if (type == MKTAG('D','A','R','K')) {

        } else if (type == MKTAG('D','I','S','O')) {

        } else if (type == MKTAG('M','A','R','K')) {

        } else if (type == MKTAG('N','U','L','L')) {

        } else if (type == MKTAG('M','L','V','I')) { /* occurs when MLV and Mnn files are concatenated */

        } else if (type == MKTAG('R','A','W','C')) {

        } else {

            av_log(avctx, AV_LOG_INFO, "unsupported tag %s, size %u\n",

                   av_fourcc2str(type), size);

        }

        avio_skip(pb, size);

    }

    return 0;

}

static int read_header(AVFormatContext *avctx)

{

    MlvContext *mlv = avctx->priv_data;

    AVIOContext *pb = avctx->pb;

    AVStream *vst = NULL, *ast = NULL;

    FFStream *vsti = NULL, *asti = NULL;

    int size, ret;

    unsigned nb_video_frames, nb_audio_frames;

    uint64_t guid;

    char guidstr[32];

    avio_skip(pb, 4);

    size = avio_rl32(pb);

    if (size < 52)

        return AVERROR_INVALIDDATA;

    avio_skip(pb, 8);

    guid = avio_rl64(pb);

    snprintf(guidstr, sizeof(guidstr), "0x%"PRIx64, guid);

    av_dict_set(&avctx->metadata, "guid", guidstr, 0);

    avio_skip(pb, 8); //fileNum, fileCount, fileFlags

    mlv->class[0] = avio_rl16(pb);

    mlv->class[1] = avio_rl16(pb);

    nb_video_frames = avio_rl32(pb);

    nb_audio_frames = avio_rl32(pb);

    if (nb_video_frames && mlv->class[0]) {

        vst = avformat_new_stream(avctx, NULL);

        if (!vst)

            return AVERROR(ENOMEM);

        vsti = ffstream(vst);

        vst->id = 0;

        vst->nb_frames = nb_video_frames;

        if ((mlv->class[0] & (MLV_CLASS_FLAG_DELTA|MLV_CLASS_FLAG_LZMA)))

            avpriv_request_sample(avctx, "compression");

        vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

        switch (mlv->class[0] & ~(MLV_CLASS_FLAG_DELTA|MLV_CLASS_FLAG_LZMA)) {

        case MLV_VIDEO_CLASS_RAW:

            vst->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;

            break;

        case MLV_VIDEO_CLASS_YUV:

            vst->codecpar->format   = AV_PIX_FMT_YUV420P;

            vst->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;

            vst->codecpar->codec_tag = 0;

            break;

        case MLV_CLASS_FLAG_LJ92|MLV_VIDEO_CLASS_RAW:

            vst->codecpar->codec_id = AV_CODEC_ID_TIFF;

            break;

        case MLV_VIDEO_CLASS_JPEG:

            vst->codecpar->codec_id = AV_CODEC_ID_MJPEG;

            vst->codecpar->codec_tag = 0;

            break;

        case MLV_VIDEO_CLASS_H264:

            vst->codecpar->codec_id = AV_CODEC_ID_H264;

            vst->codecpar->codec_tag = 0;

            break;

        default:

            avpriv_request_sample(avctx, "unknown video class");

        }

    }

    if (nb_audio_frames && mlv->class[1]) {

        ast = avformat_new_stream(avctx, NULL);

        if (!ast)

            return AVERROR(ENOMEM);

        asti = ffstream(ast);

        ast->id = 1;

        ast->nb_frames = nb_audio_frames;

        if ((mlv->class[1] & MLV_CLASS_FLAG_LZMA))

            avpriv_request_sample(avctx, "compression");

        if ((mlv->class[1] & ~MLV_CLASS_FLAG_LZMA) != MLV_AUDIO_CLASS_WAV)

            avpriv_request_sample(avctx, "unknown audio class");

        ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

        avpriv_set_pts_info(ast, 33, 1, ast->codecpar->sample_rate);

    }

    if (vst) {

       AVRational framerate;

       framerate.num = avio_rl32(pb);

       framerate.den = avio_rl32(pb);

       avpriv_set_pts_info(vst, 64, framerate.den, framerate.num);

    } else

       avio_skip(pb, 8);

    avio_skip(pb, size - 52);

    /* scan primary file */

    mlv->pb[100] = avctx->pb;

    ret = scan_file(avctx, vst, ast, 100);

    if (ret < 0)

        return ret;

    /* scan secondary files */

    if (strlen(avctx->url) > 2) {

        int i;

        char *filename = av_strdup(avctx->url);

        if (!filename)

            return AVERROR(ENOMEM);

        for (i = 0; i < 100; i++) {

            snprintf(filename + strlen(filename) - 2, 3, "%02d", i);

            if (avctx->io_open(avctx, &mlv->pb[i], filename, AVIO_FLAG_READ, NULL) < 0)

                break;

            if (check_file_header(mlv->pb[i], guid) < 0) {

                av_log(avctx, AV_LOG_WARNING, "ignoring %s; bad format or guid mismatch\n", filename);

                ff_format_io_close(avctx, &mlv->pb[i]);

                continue;

            }

            av_log(avctx, AV_LOG_INFO, "scanning %s\n", filename);

            ret = scan_file(avctx, vst, ast, i);

            if (ret < 0) {

                av_log(avctx, AV_LOG_WARNING, "ignoring %s; %s\n", filename, av_err2str(ret));

                ff_format_io_close(avctx, &mlv->pb[i]);

                continue;

            }

        }

        av_free(filename);

    }

    if (vst)

        vst->duration = vsti->nb_index_entries;

    if (ast)

        ast->duration = asti->nb_index_entries;

    if ((vst && !vsti->nb_index_entries) || (ast && !asti->nb_index_entries)) {

        av_log(avctx, AV_LOG_ERROR, "no index entries found\n");

        return AVERROR_INVALIDDATA;

    }

    if (vst && ast)

        avio_seek(pb, FFMIN(vsti->index_entries[0].pos, asti->index_entries[0].pos), SEEK_SET);

    else if (vst)

        avio_seek(pb, vsti->index_entries[0].pos, SEEK_SET);

    else if (ast)

        avio_seek(pb, asti->index_entries[0].pos, SEEK_SET);

    return 0;

}

static void write_tiff_short(PutByteContext *pb, int tag, int value)

{

    bytestream2_put_le16(pb, tag);

    bytestream2_put_le16(pb, AV_TIFF_SHORT);

    bytestream2_put_le32(pb, 1);

    bytestream2_put_le16(pb, value);

    bytestream2_put_le16(pb, 0);

}

static void write_tiff_short2(PutByteContext *pb, int tag, int v1, int v2)

{

    bytestream2_put_le16(pb, tag);

    bytestream2_put_le16(pb, AV_TIFF_SHORT);

    bytestream2_put_le32(pb, 2);

    bytestream2_put_le16(pb, v1);

    bytestream2_put_le16(pb, v2);

}

static void write_tiff_long(PutByteContext *pb, int tag, int value)

{

    bytestream2_put_le16(pb, tag);

    bytestream2_put_le16(pb, AV_TIFF_LONG);

    bytestream2_put_le32(pb, 1);

    bytestream2_put_le32(pb, value);

}

static void write_tiff_byte4(PutByteContext *pb, int tag, int v1, int v2, int v3, int v4)

{

    bytestream2_put_le16(pb, tag);

    bytestream2_put_le16(pb, AV_TIFF_BYTE);

    bytestream2_put_le32(pb, 4);

    bytestream2_put_byte(pb, v1);

    bytestream2_put_byte(pb, v2);

    bytestream2_put_byte(pb, v3);

    bytestream2_put_byte(pb, v4);

}

static int get_packet_lj92(AVFormatContext *avctx, AVStream *st, AVIOContext *pbio, AVPacket *pkt, int64_t size)

{

    MlvContext *mlv = avctx->priv_data;

    PutByteContext pbctx, *pb = &pbctx;

    int ret, header_size;

    uint8_t *stripofs, *matrixofs;

#define MAX_HEADER_SIZE 2048

    if ((uint64_t)size > INT32_MAX - MAX_HEADER_SIZE)

        return AVERROR_PATCHWELCOME;

    if ((ret = av_new_packet(pkt, size + MAX_HEADER_SIZE)) < 0)

        return ret;

    bytestream2_init_writer(pb, pkt->data, MAX_HEADER_SIZE);

    bytestream2_put_le16(pb, 0x4949);

    bytestream2_put_le16(pb, 42);

    bytestream2_put_le32(pb, 8);

    bytestream2_put_le16(pb, 18); /* nb_entries */

    write_tiff_long(pb, TIFF_SUBFILE, 0);

    write_tiff_long(pb, TIFF_WIDTH, st->codecpar->width);

    write_tiff_long(pb, TIFF_HEIGHT, st->codecpar->height);

    write_tiff_long(pb, TIFF_BPP,  st->codecpar->bits_per_coded_sample);

    write_tiff_short(pb, TIFF_COMPR, TIFF_NEWJPEG);

    write_tiff_short(pb, TIFF_PHOTOMETRIC, TIFF_PHOTOMETRIC_CFA);

    write_tiff_short(pb, TIFF_FILL_ORDER, 1);

    write_tiff_long(pb, TIFF_STRIP_OFFS, 0); /* stripofs */

    stripofs = pb->buffer - 4;

    write_tiff_long(pb, TIFF_SAMPLES_PER_PIXEL, 1);

    write_tiff_short(pb, TIFF_ROWSPERSTRIP, st->codecpar->height);

    write_tiff_long(pb, TIFF_STRIP_SIZE, size);

    write_tiff_short(pb, TIFF_PLANAR, 1);

    write_tiff_short2(pb, TIFF_CFA_PATTERN_DIM, 2, 2);

    write_tiff_byte4(pb, TIFF_CFA_PATTERN, 0, 1, 1, 2);

    write_tiff_byte4(pb, DNG_VERSION, 1, 4, 0, 0);

    write_tiff_long(pb, DNG_BLACK_LEVEL, mlv->black_level);

    write_tiff_long(pb, DNG_WHITE_LEVEL, mlv->white_level);

    bytestream2_put_le16(pb, DNG_COLOR_MATRIX1);

    bytestream2_put_le16(pb, AV_TIFF_SRATIONAL);

    bytestream2_put_le32(pb, 9);

    bytestream2_put_le32(pb, 0); /* matrixofs */

    matrixofs = pb->buffer - 4;

    bytestream2_put_le32(pb, 0);

    AV_WL32(matrixofs, bytestream2_tell_p(pb));

    for (int i = 0; i < 9; i++) {

        bytestream2_put_le32(pb, mlv->color_matrix1[i][0]);

        bytestream2_put_le32(pb, mlv->color_matrix1[i][1]);

    }

    header_size = bytestream2_tell_p(pb);

    AV_WL32(stripofs, header_size);

    ret = avio_read(pbio, pkt->data + header_size, size);

    if (ret < 0)

        return ret;

    return 0;

}

static int read_packet(AVFormatContext *avctx, AVPacket *pkt)

{

    MlvContext *mlv = avctx->priv_data;

    AVIOContext *pb;

    AVStream *st;

    FFStream *sti;

    int index, ret;

    unsigned int size, space;

    if (!avctx->nb_streams)

        return AVERROR_EOF;

    st = avctx->streams[mlv->stream_index];

    sti = ffstream(st);

    if (mlv->pts >= st->duration)

        return AVERROR_EOF;

    index = av_index_search_timestamp(st, mlv->pts, AVSEEK_FLAG_ANY);

    if (index < 0) {

        av_log(avctx, AV_LOG_ERROR, "could not find index entry for frame %"PRId64"\n", mlv->pts);

        return AVERROR_INVALIDDATA;

    }

    pb = mlv->pb[sti->index_entries[index].size];

    if (!pb) {

        ret = FFERROR_REDO;

        goto next_packet;

    }

    avio_seek(pb, sti->index_entries[index].pos, SEEK_SET);

    avio_skip(pb, 4); // blockType

    size = avio_rl32(pb);

    if (size < 16)

        return AVERROR_INVALIDDATA;

    avio_skip(pb, 12); //timestamp, frameNumber

    size -= 12;

    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {

        if (size < 8)

            return AVERROR_INVALIDDATA;

        avio_skip(pb, 8); // cropPosX, cropPosY, panPosX, panPosY

        size -= 8;

    }

    space = avio_rl32(pb);

    if (size < space + 4LL)

        return AVERROR_INVALIDDATA;

    avio_skip(pb, space);

    size -= space;

    if ((mlv->class[st->id] & (MLV_CLASS_FLAG_DELTA|MLV_CLASS_FLAG_LZMA))) {

        ret = AVERROR_PATCHWELCOME;

    } else if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {

        if (st->codecpar->codec_id == AV_CODEC_ID_TIFF)

            ret = get_packet_lj92(avctx, st, pb, pkt, size);

        else

            ret = av_get_packet(pb, pkt, (st->codecpar->width * st->codecpar->height * st->codecpar->bits_per_coded_sample + 7) >> 3);

    } else { // AVMEDIA_TYPE_AUDIO

        ret = av_get_packet(pb, pkt, size - 4);

    }

    if (ret < 0)

        return ret;

    pkt->stream_index = mlv->stream_index;

    pkt->pts = mlv->pts;

    ret = 0;

next_packet:

    mlv->stream_index++;

    if (mlv->stream_index == avctx->nb_streams) {

        mlv->stream_index = 0;

        mlv->pts++;

    }

    return ret;

}

static int read_seek(AVFormatContext *avctx, int stream_index, int64_t timestamp, int flags)

{

    MlvContext *mlv = avctx->priv_data;

    if ((flags & AVSEEK_FLAG_FRAME) || (flags & AVSEEK_FLAG_BYTE))

        return AVERROR(ENOSYS);

    if (!(avctx->pb->seekable & AVIO_SEEKABLE_NORMAL))

        return AVERROR(ENOSYS);

    mlv->pts = timestamp;

    return 0;

}

static int read_close(AVFormatContext *s)

{

    MlvContext *mlv = s->priv_data;

    int i;

    for (i = 0; i < 100; i++)

        ff_format_io_close(s, &mlv->pb[i]);

    return 0;

}

const FFInputFormat ff_mlv_demuxer = {

    .p.name         = "mlv",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Magic Lantern Video (MLV)"),

    .priv_data_size = sizeof(MlvContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = probe,

    .read_header    = read_header,

    .read_packet    = read_packet,

    .read_close     = read_close,

    .read_seek      = read_seek,

};