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ffmpeg / libavformat / bethsoftvid.c @ 0ab1ebea

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/*
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 * Bethsoft VID format Demuxer
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 * Copyright (c) 2007 Nicholas Tung
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg 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 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg 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 FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file bethsoftvid.c
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 * @brief Bethesda Softworks VID (.vid) file demuxer
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 * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
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 * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
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 * @sa http://www.svatopluk.com/andux/docs/dfvid.html
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 */
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#include "avformat.h"
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#include "bethsoftvideo.h"
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typedef struct BVID_DemuxContext
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{
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    int nframes;
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    /** delay value between frames, added to individual frame delay.
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     * custom units, which will be added to other custom units (~=16ms according
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     * to free, unofficial documentation) */
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    int bethsoft_global_delay;
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    /** video presentation time stamp.
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     * delay = 16 milliseconds * (global_delay + per_frame_delay) */
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    int video_pts;
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    int is_finished;
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} BVID_DemuxContext;
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static int vid_probe(AVProbeData *p)
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{
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    // little endian VID tag, file starts with "VID\0"
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    if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
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        return 0;
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    return AVPROBE_SCORE_MAX;
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}
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static int vid_read_header(AVFormatContext *s,
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                            AVFormatParameters *ap)
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{
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    BVID_DemuxContext *vid = s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    AVStream *stream;
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    /* load main header. Contents:
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    *    bytes: 'V' 'I' 'D'
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    *    int16s: always_512, nframes, width, height, delay, always_14
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    */
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    url_fseek(pb, 5, SEEK_CUR);
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    vid->nframes = get_le16(pb);
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    stream = av_new_stream(s, 0);
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    if (!stream)
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        return AVERROR(ENOMEM);
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    av_set_pts_info(stream, 32, 1, 60);     // 16 ms increments, i.e. 60 fps
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    stream->codec->codec_type = CODEC_TYPE_VIDEO;
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    stream->codec->codec_id = CODEC_ID_BETHSOFTVID;
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    stream->codec->width = get_le16(pb);
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    stream->codec->height = get_le16(pb);
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    stream->codec->pix_fmt = PIX_FMT_PAL8;
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    vid->bethsoft_global_delay = get_le16(pb);
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    get_le16(pb);
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    // done with video codec, set up audio codec
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    stream = av_new_stream(s, 0);
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    if (!stream)
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        return AVERROR(ENOMEM);
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    stream->codec->codec_type = CODEC_TYPE_AUDIO;
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    stream->codec->codec_id = CODEC_ID_PCM_U8;
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    stream->codec->channels = 1;
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    stream->codec->sample_rate = 11025;
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    stream->codec->bits_per_sample = 8;
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    stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_sample;
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    return 0;
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}
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#define BUFFER_PADDING_SIZE 1000
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static int read_frame(BVID_DemuxContext *vid, ByteIOContext *pb, AVPacket *pkt,
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                      uint8_t block_type, AVFormatContext *s, int npixels)
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{
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    uint8_t * vidbuf_start = NULL;
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    int vidbuf_nbytes = 0;
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    int code;
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    int bytes_copied = 0;
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    int position;
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    unsigned int vidbuf_capacity;
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    vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
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    if(!vidbuf_start)
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        return AVERROR(ENOMEM);
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    // save the file position for the packet, include block type
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    position = url_ftell(pb) - 1;
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    vidbuf_start[vidbuf_nbytes++] = block_type;
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    // get the video delay (next int16), and set the presentation time
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    vid->video_pts += vid->bethsoft_global_delay + get_le16(pb);
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    // set the y offset if it exists (decoder header data should be in data section)
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    if(block_type == VIDEO_YOFF_P_FRAME){
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        if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)
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            goto fail;
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        vidbuf_nbytes += 2;
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    }
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    do{
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        vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
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        if(!vidbuf_start)
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            return AVERROR(ENOMEM);
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        code = get_byte(pb);
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        vidbuf_start[vidbuf_nbytes++] = code;
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        if(code >= 0x80){ // rle sequence
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            if(block_type == VIDEO_I_FRAME)
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                vidbuf_start[vidbuf_nbytes++] = get_byte(pb);
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        } else if(code){ // plain sequence
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            if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], code) != code)
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                goto fail;
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            vidbuf_nbytes += code;
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        }
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        bytes_copied += code & 0x7F;
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        if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
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            // may contain a 0 byte even if read all pixels
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            if(get_byte(pb))
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                url_fseek(pb, -1, SEEK_CUR);
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            break;
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        }
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        if(bytes_copied > npixels)
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            goto fail;
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    } while(code);
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    // copy data into packet
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    if(av_new_packet(pkt, vidbuf_nbytes) < 0)
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        goto fail;
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    memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
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    av_free(vidbuf_start);
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    pkt->pos = position;
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    pkt->stream_index = 0;  // use the video decoder, which was initialized as the first stream
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    pkt->pts = vid->video_pts;
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    vid->nframes--;  // used to check if all the frames were read
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    return vidbuf_nbytes;
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fail:
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    av_free(vidbuf_start);
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    return -1;
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}
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static int vid_read_packet(AVFormatContext *s,
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                           AVPacket *pkt)
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{
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    BVID_DemuxContext *vid = s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    unsigned char block_type;
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    int audio_length;
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    int ret_value;
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    if(vid->is_finished || url_feof(pb))
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        return AVERROR(EIO);
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    block_type = get_byte(pb);
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    switch(block_type){
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        case PALETTE_BLOCK:
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            url_fseek(pb, -1, SEEK_CUR);     // include block type
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            ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);
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            if(ret_value != 3 * 256 + 1){
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                av_free_packet(pkt);
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                return AVERROR(EIO);
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            }
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            pkt->stream_index = 0;
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            return ret_value;
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        case FIRST_AUDIO_BLOCK:
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            get_le16(pb);
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            // soundblaster DAC used for sample rate, as on specification page (link above)
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            s->streams[1]->codec->sample_rate = 1000000 / (256 - get_byte(pb));
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            s->streams[1]->codec->bit_rate = s->streams[1]->codec->channels * s->streams[1]->codec->sample_rate * s->streams[1]->codec->bits_per_sample;
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        case AUDIO_BLOCK:
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            audio_length = get_le16(pb);
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            ret_value = av_get_packet(pb, pkt, audio_length);
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            pkt->stream_index = 1;
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            return (ret_value != audio_length ? AVERROR(EIO) : ret_value);
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        case VIDEO_P_FRAME:
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        case VIDEO_YOFF_P_FRAME:
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        case VIDEO_I_FRAME:
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            return read_frame(vid, pb, pkt, block_type, s,
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                              s->streams[0]->codec->width * s->streams[0]->codec->height);
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        case EOF_BLOCK:
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            if(vid->nframes != 0)
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                av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
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            vid->is_finished = 1;
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            return AVERROR(EIO);
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        default:
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            av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
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                   block_type, block_type, block_type); return -1;
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    }
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    return 0;
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}
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AVInputFormat bethsoftvid_demuxer = {
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    "bethsoftvid",
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    "Bethesda Softworks 'Daggerfall' VID format",
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    sizeof(BVID_DemuxContext),
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    vid_probe,
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    vid_read_header,
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    vid_read_packet,
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};