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ffmpeg / libavformat / sierravmd.c @ 01f4895c

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/*
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 * Sierra VMD Format Demuxer
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 * Copyright (c) 2004 The ffmpeg Project
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 */
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/**
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 * @file sierravmd.c
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 * Sierra VMD file demuxer
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 * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
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 * for more information on the Sierra VMD file format, visit:
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 *   http://www.pcisys.net/~melanson/codecs/
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 */
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#include "avformat.h"
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#define VMD_HEADER_SIZE 0x0330
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#define BYTES_PER_FRAME_RECORD 16
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typedef struct {
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  int stream_index;
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  offset_t frame_offset;
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  unsigned int frame_size;
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  int64_t pts;
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  int keyframe;
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  unsigned char frame_record[BYTES_PER_FRAME_RECORD];
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} vmd_frame_t;
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typedef struct VmdDemuxContext {
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    int video_stream_index;
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    int audio_stream_index;
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    unsigned int audio_type;
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    unsigned int audio_samplerate;
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    unsigned int audio_bits;
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    unsigned int audio_channels;
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    unsigned int frame_count;
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    vmd_frame_t *frame_table;
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    unsigned int current_frame;
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    int sample_rate;
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    int64_t audio_sample_counter;
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    int audio_frame_divisor;
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    int audio_block_align;
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    unsigned char vmd_header[VMD_HEADER_SIZE];
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} VmdDemuxContext;
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static int vmd_probe(AVProbeData *p)
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{
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    if (p->buf_size < 2)
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        return 0;
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    /* check if the first 2 bytes of the file contain the appropriate size
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     * of a VMD header chunk */
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    if (LE_16(&p->buf[0]) != VMD_HEADER_SIZE - 2)
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        return 0;
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    /* only return half certainty since this check is a bit sketchy */
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    return AVPROBE_SCORE_MAX / 2;
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}
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/* This is a support function to determine the duration, in sample
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 * frames, of a particular audio chunk, taking into account silent
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 * encodings. */
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static int vmd_calculate_audio_duration(unsigned char *audio_chunk,
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    int audio_chunk_size, int block_align)
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{
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    unsigned char *p = audio_chunk + 16;
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    unsigned char *p_end = audio_chunk + audio_chunk_size;
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    int total_samples = 0;
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    unsigned int sound_flags;
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    if (audio_chunk_size < 16)
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        return 0;
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    sound_flags = LE_32(p);
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    p += 4;
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    while (p < p_end) {
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        total_samples += block_align;
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        if ((sound_flags & 0x01) == 0)
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            p += block_align;
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        sound_flags >>= 1;
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    }
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    return total_samples;
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}
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static int vmd_read_header(AVFormatContext *s,
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                           AVFormatParameters *ap)
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{
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    VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    AVStream *st;
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    unsigned int toc_offset;
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    unsigned char *raw_frame_table;
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    int raw_frame_table_size;
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    unsigned char *current_frame_record;
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    offset_t current_offset;
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    int i;
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    unsigned int total_frames;
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    int64_t video_pts_inc;
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    int64_t current_video_pts = 0;
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    /* fetch the main header, including the 2 header length bytes */
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    url_fseek(pb, 0, SEEK_SET);
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    if (get_buffer(pb, vmd->vmd_header, VMD_HEADER_SIZE) != VMD_HEADER_SIZE)
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        return AVERROR_IO;
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    vmd->audio_sample_counter = 0;
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    vmd->audio_frame_divisor = 1;
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    vmd->audio_block_align = 1;
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    /* start up the decoders */
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    st = av_new_stream(s, 0);
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    if (!st)
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        return AVERROR_NOMEM;
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    av_set_pts_info(st, 33, 1, 90000);
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    vmd->video_stream_index = st->index;
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    st->codec->codec_type = CODEC_TYPE_VIDEO;
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    st->codec->codec_id = CODEC_ID_VMDVIDEO;
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    st->codec->codec_tag = 0;  /* no fourcc */
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    st->codec->width = LE_16(&vmd->vmd_header[12]);
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    st->codec->height = LE_16(&vmd->vmd_header[14]);
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    st->codec->extradata_size = VMD_HEADER_SIZE;
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    st->codec->extradata = av_malloc(VMD_HEADER_SIZE);
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    memcpy(st->codec->extradata, vmd->vmd_header, VMD_HEADER_SIZE);
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    /* if sample rate is 0, assume no audio */
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    vmd->sample_rate = LE_16(&vmd->vmd_header[804]);
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    if (vmd->sample_rate) {
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        st = av_new_stream(s, 0);
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        if (!st)
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            return AVERROR_NOMEM;
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        av_set_pts_info(st, 33, 1, 90000);
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        vmd->audio_stream_index = st->index;
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        st->codec->codec_type = CODEC_TYPE_AUDIO;
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        st->codec->codec_id = CODEC_ID_VMDAUDIO;
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        st->codec->codec_tag = 0;  /* no codec tag */
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        st->codec->channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
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        st->codec->sample_rate = vmd->sample_rate;
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        st->codec->block_align = vmd->audio_block_align = 
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            LE_16(&vmd->vmd_header[806]);
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        if (st->codec->block_align & 0x8000) {
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            st->codec->bits_per_sample = 16;
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            st->codec->block_align = -(st->codec->block_align - 0x10000);
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        } else
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            st->codec->bits_per_sample = 16;
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//            st->codec->bits_per_sample = 8;
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        st->codec->bit_rate = st->codec->sample_rate * 
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            st->codec->bits_per_sample * st->codec->channels;
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        /* for calculating pts */
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        vmd->audio_frame_divisor = st->codec->bits_per_sample / 8 / 
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            st->codec->channels;
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        video_pts_inc = 90000;
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        video_pts_inc *= st->codec->block_align;
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        video_pts_inc /= st->codec->sample_rate;
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    } else {
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        /* if no audio, assume 10 frames/second */
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        video_pts_inc = 90000 / 10;
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    }
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    /* skip over the offset table and load the table of contents; don't 
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     * care about the offset table since demuxer will calculate those 
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     * independently */
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    toc_offset = LE_32(&vmd->vmd_header[812]);
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    vmd->frame_count = LE_16(&vmd->vmd_header[6]);
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    url_fseek(pb, toc_offset + vmd->frame_count * 6, SEEK_SET);
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    /* each on-disk VMD frame has an audio part and a video part; demuxer
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     * accounts them separately */
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    if(vmd->sample_rate)
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        vmd->frame_count *= 2;
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    raw_frame_table = NULL;
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    vmd->frame_table = NULL;
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    raw_frame_table_size = vmd->frame_count * BYTES_PER_FRAME_RECORD;
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    raw_frame_table = av_malloc(raw_frame_table_size);
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    vmd->frame_table = av_malloc(vmd->frame_count * sizeof(vmd_frame_t));
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    if (!raw_frame_table || !vmd->frame_table) {
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        av_free(raw_frame_table);
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        av_free(vmd->frame_table);
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        return AVERROR_NOMEM;
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    }
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    if (get_buffer(pb, raw_frame_table, raw_frame_table_size) != 
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        raw_frame_table_size) {
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        av_free(raw_frame_table);
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        av_free(vmd->frame_table);
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        return AVERROR_IO;
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    }
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    current_offset = LE_32(&vmd->vmd_header[20]);
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    current_frame_record = raw_frame_table;
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    total_frames = vmd->frame_count;
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    i = 0;
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    while (total_frames--) {
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        /* if the frame size is 0, do not count the frame and bring the
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         * total frame count down */
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        // note, we limit the size to 1Gb to ensure that we dont end up overflowing the size integer used to allocate the memory
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        vmd->frame_table[i].frame_size = LE_32(&current_frame_record[2]) & 0x3FFFFFFF; 
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        /* this logic is present so that 0-length audio chunks are not
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         * accounted */
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        if (!vmd->frame_table[i].frame_size) {
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            vmd->frame_count--;  /* one less frame to count */
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            current_frame_record += BYTES_PER_FRAME_RECORD;
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            continue;
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        }
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        if (current_frame_record[0] == 0x02)
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            vmd->frame_table[i].stream_index = vmd->video_stream_index;
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        else
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            vmd->frame_table[i].stream_index = vmd->audio_stream_index;
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        vmd->frame_table[i].frame_offset = current_offset;
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        current_offset += vmd->frame_table[i].frame_size;
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        memcpy(vmd->frame_table[i].frame_record, current_frame_record,
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            BYTES_PER_FRAME_RECORD);
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        /* figure out the pts for this frame */
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        if (current_frame_record[0] == 0x02) {
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            vmd->frame_table[i].pts = current_video_pts;
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            current_video_pts += video_pts_inc;
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        } else if (current_frame_record[0] == 0x01) {
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            /* figure out the pts during the dispatch phase */
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            vmd->frame_table[i].pts = 0;
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        }
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        current_frame_record += BYTES_PER_FRAME_RECORD;
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        i++;
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    }
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    av_free(raw_frame_table);
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    vmd->current_frame = 0;
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    return 0;
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}
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static int vmd_read_packet(AVFormatContext *s,
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                           AVPacket *pkt)
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{
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    VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    int ret = 0;
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    vmd_frame_t *frame;
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    if (vmd->current_frame >= vmd->frame_count)
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        return AVERROR_IO;
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    frame = &vmd->frame_table[vmd->current_frame];
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    /* position the stream (will probably be there already) */
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    url_fseek(pb, frame->frame_offset, SEEK_SET);
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    if (av_new_packet(pkt, frame->frame_size + BYTES_PER_FRAME_RECORD))
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        return AVERROR_NOMEM;
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    pkt->pos= url_ftell(pb);
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    memcpy(pkt->data, frame->frame_record, BYTES_PER_FRAME_RECORD);
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    ret = get_buffer(pb, pkt->data + BYTES_PER_FRAME_RECORD, 
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        frame->frame_size);
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    if (ret != frame->frame_size) {
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        av_free_packet(pkt);
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        ret = AVERROR_IO;
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    }
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    pkt->stream_index = frame->stream_index;
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    if (frame->frame_record[0] == 0x02)
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        pkt->pts = frame->pts;
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    else {
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        pkt->pts = vmd->audio_sample_counter;
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        pkt->pts *= 90000;
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        pkt->pts /= vmd->sample_rate;
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//        pkt->pts /= vmd->audio_frame_divisor;
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        vmd->audio_sample_counter += vmd_calculate_audio_duration(
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            pkt->data, pkt->size, vmd->audio_block_align);
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    }
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av_log(NULL, AV_LOG_INFO, " dispatching %s frame with %d bytes and pts %lld (%0.1f sec)\n",
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  (frame->frame_record[0] == 0x02) ? "video" : "audio",
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  frame->frame_size + BYTES_PER_FRAME_RECORD,
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  pkt->pts, (float)(pkt->pts / 90000.0));
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    vmd->current_frame++;
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    return ret;
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}
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static int vmd_read_close(AVFormatContext *s)
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{
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    VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
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    av_free(vmd->frame_table);
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    return 0;
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}
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static AVInputFormat vmd_iformat = {
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    "vmd",
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    "Sierra VMD format",
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    sizeof(VmdDemuxContext),
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    vmd_probe,
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    vmd_read_header,
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    vmd_read_packet,
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    vmd_read_close,
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};
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int vmd_init(void)
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{
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    av_register_input_format(&vmd_iformat);
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    return 0;
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}