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Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
305 lines
9.2 KiB
C
305 lines
9.2 KiB
C
/*
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* Wing Commander III Movie (.mve) File Demuxer
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* Copyright (c) 2003 The ffmpeg Project
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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
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* Wing Commander III Movie file demuxer
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* by Mike Melanson (melanson@pcisys.net)
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* for more information on the WC3 .mve file format, visit:
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* http://www.pcisys.net/~melanson/codecs/
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*/
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#include "libavutil/channel_layout.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/dict.h"
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#include "avformat.h"
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#include "internal.h"
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#define FORM_TAG MKTAG('F', 'O', 'R', 'M')
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#define MOVE_TAG MKTAG('M', 'O', 'V', 'E')
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#define PC__TAG MKTAG('_', 'P', 'C', '_')
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#define SOND_TAG MKTAG('S', 'O', 'N', 'D')
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#define BNAM_TAG MKTAG('B', 'N', 'A', 'M')
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#define SIZE_TAG MKTAG('S', 'I', 'Z', 'E')
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#define PALT_TAG MKTAG('P', 'A', 'L', 'T')
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#define INDX_TAG MKTAG('I', 'N', 'D', 'X')
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#define BRCH_TAG MKTAG('B', 'R', 'C', 'H')
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#define SHOT_TAG MKTAG('S', 'H', 'O', 'T')
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#define VGA__TAG MKTAG('V', 'G', 'A', ' ')
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#define TEXT_TAG MKTAG('T', 'E', 'X', 'T')
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#define AUDI_TAG MKTAG('A', 'U', 'D', 'I')
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/* video resolution unless otherwise specified */
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#define WC3_DEFAULT_WIDTH 320
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#define WC3_DEFAULT_HEIGHT 165
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/* always use the same PCM audio parameters */
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#define WC3_SAMPLE_RATE 22050
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#define WC3_AUDIO_CHANNELS 1
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#define WC3_AUDIO_BITS 16
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/* nice, constant framerate */
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#define WC3_FRAME_FPS 15
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#define PALETTE_SIZE (256 * 3)
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typedef struct Wc3DemuxContext {
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int width;
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int height;
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int64_t pts;
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int video_stream_index;
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int audio_stream_index;
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AVPacket vpkt;
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} Wc3DemuxContext;
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static int wc3_probe(AVProbeData *p)
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{
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if (p->buf_size < 12)
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return 0;
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if ((AV_RL32(&p->buf[0]) != FORM_TAG) ||
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(AV_RL32(&p->buf[8]) != MOVE_TAG))
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return 0;
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return AVPROBE_SCORE_MAX;
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}
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static int wc3_read_header(AVFormatContext *s)
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{
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Wc3DemuxContext *wc3 = s->priv_data;
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AVIOContext *pb = s->pb;
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unsigned int fourcc_tag;
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unsigned int size;
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AVStream *st;
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int ret = 0;
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char *buffer;
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/* default context members */
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wc3->width = WC3_DEFAULT_WIDTH;
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wc3->height = WC3_DEFAULT_HEIGHT;
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wc3->pts = 0;
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wc3->video_stream_index = wc3->audio_stream_index = 0;
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av_init_packet(&wc3->vpkt);
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wc3->vpkt.data = NULL; wc3->vpkt.size = 0;
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/* skip the first 3 32-bit numbers */
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avio_skip(pb, 12);
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/* traverse through the chunks and load the header information before
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* the first BRCH tag */
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fourcc_tag = avio_rl32(pb);
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size = (avio_rb32(pb) + 1) & (~1);
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do {
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switch (fourcc_tag) {
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case SOND_TAG:
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case INDX_TAG:
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/* SOND unknown, INDX unnecessary; ignore both */
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avio_skip(pb, size);
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break;
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case PC__TAG:
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/* number of palettes, unneeded */
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avio_skip(pb, 12);
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break;
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case BNAM_TAG:
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/* load up the name */
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buffer = av_malloc(size+1);
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if (!buffer)
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return AVERROR(ENOMEM);
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if ((ret = avio_read(pb, buffer, size)) != size)
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return AVERROR(EIO);
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buffer[size] = 0;
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av_dict_set(&s->metadata, "title", buffer,
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AV_DICT_DONT_STRDUP_VAL);
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break;
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case SIZE_TAG:
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/* video resolution override */
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wc3->width = avio_rl32(pb);
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wc3->height = avio_rl32(pb);
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break;
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case PALT_TAG:
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/* one of several palettes */
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avio_seek(pb, -8, SEEK_CUR);
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av_append_packet(pb, &wc3->vpkt, 8 + PALETTE_SIZE);
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break;
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default:
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av_log(s, AV_LOG_ERROR, " unrecognized WC3 chunk: %c%c%c%c (0x%02X%02X%02X%02X)\n",
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(uint8_t)fourcc_tag, (uint8_t)(fourcc_tag >> 8), (uint8_t)(fourcc_tag >> 16), (uint8_t)(fourcc_tag >> 24),
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(uint8_t)fourcc_tag, (uint8_t)(fourcc_tag >> 8), (uint8_t)(fourcc_tag >> 16), (uint8_t)(fourcc_tag >> 24));
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return AVERROR_INVALIDDATA;
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}
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fourcc_tag = avio_rl32(pb);
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/* chunk sizes are 16-bit aligned */
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size = (avio_rb32(pb) + 1) & (~1);
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if (pb->eof_reached)
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return AVERROR(EIO);
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} while (fourcc_tag != BRCH_TAG);
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/* initialize the decoder streams */
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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avpriv_set_pts_info(st, 33, 1, WC3_FRAME_FPS);
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wc3->video_stream_index = st->index;
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st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
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st->codecpar->codec_id = AV_CODEC_ID_XAN_WC3;
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st->codecpar->codec_tag = 0; /* no fourcc */
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st->codecpar->width = wc3->width;
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st->codecpar->height = wc3->height;
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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avpriv_set_pts_info(st, 33, 1, WC3_FRAME_FPS);
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wc3->audio_stream_index = st->index;
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
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st->codecpar->codec_tag = 1;
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st->codecpar->channels = WC3_AUDIO_CHANNELS;
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st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
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st->codecpar->bits_per_coded_sample = WC3_AUDIO_BITS;
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st->codecpar->sample_rate = WC3_SAMPLE_RATE;
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st->codecpar->bit_rate = st->codecpar->channels * st->codecpar->sample_rate *
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st->codecpar->bits_per_coded_sample;
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st->codecpar->block_align = WC3_AUDIO_BITS * WC3_AUDIO_CHANNELS;
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return 0;
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}
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static int wc3_read_packet(AVFormatContext *s,
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AVPacket *pkt)
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{
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Wc3DemuxContext *wc3 = s->priv_data;
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AVIOContext *pb = s->pb;
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unsigned int fourcc_tag;
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unsigned int size;
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int packet_read = 0;
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int ret = 0;
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unsigned char text[1024];
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while (!packet_read) {
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fourcc_tag = avio_rl32(pb);
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/* chunk sizes are 16-bit aligned */
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size = (avio_rb32(pb) + 1) & (~1);
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if (pb->eof_reached)
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return AVERROR(EIO);
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switch (fourcc_tag) {
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case BRCH_TAG:
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/* no-op */
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break;
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case SHOT_TAG:
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/* load up new palette */
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avio_seek(pb, -8, SEEK_CUR);
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av_append_packet(pb, &wc3->vpkt, 8 + 4);
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break;
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case VGA__TAG:
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/* send out video chunk */
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avio_seek(pb, -8, SEEK_CUR);
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ret= av_append_packet(pb, &wc3->vpkt, 8 + size);
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// ignore error if we have some data
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if (wc3->vpkt.size > 0)
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ret = 0;
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*pkt = wc3->vpkt;
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wc3->vpkt.data = NULL; wc3->vpkt.size = 0;
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pkt->stream_index = wc3->video_stream_index;
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pkt->pts = wc3->pts;
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packet_read = 1;
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break;
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case TEXT_TAG:
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/* subtitle chunk */
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#if 0
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avio_skip(pb, size);
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#else
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if ((unsigned)size > sizeof(text) || (ret = avio_read(pb, text, size)) != size)
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ret = AVERROR(EIO);
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else {
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int i = 0;
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av_log (s, AV_LOG_DEBUG, "Subtitle time!\n");
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av_log (s, AV_LOG_DEBUG, " inglish: %s\n", &text[i + 1]);
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i += text[i] + 1;
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av_log (s, AV_LOG_DEBUG, " doytsch: %s\n", &text[i + 1]);
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i += text[i] + 1;
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av_log (s, AV_LOG_DEBUG, " fronsay: %s\n", &text[i + 1]);
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}
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#endif
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break;
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case AUDI_TAG:
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/* send out audio chunk */
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ret= av_get_packet(pb, pkt, size);
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pkt->stream_index = wc3->audio_stream_index;
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pkt->pts = wc3->pts;
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/* time to advance pts */
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wc3->pts++;
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packet_read = 1;
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break;
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default:
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av_log (s, AV_LOG_ERROR, " unrecognized WC3 chunk: %c%c%c%c (0x%02X%02X%02X%02X)\n",
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(uint8_t)fourcc_tag, (uint8_t)(fourcc_tag >> 8), (uint8_t)(fourcc_tag >> 16), (uint8_t)(fourcc_tag >> 24),
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(uint8_t)fourcc_tag, (uint8_t)(fourcc_tag >> 8), (uint8_t)(fourcc_tag >> 16), (uint8_t)(fourcc_tag >> 24));
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ret = AVERROR_INVALIDDATA;
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packet_read = 1;
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break;
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}
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}
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return ret;
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}
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static int wc3_read_close(AVFormatContext *s)
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{
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Wc3DemuxContext *wc3 = s->priv_data;
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if (wc3->vpkt.size > 0)
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av_packet_unref(&wc3->vpkt);
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return 0;
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}
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AVInputFormat ff_wc3_demuxer = {
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.name = "wc3movie",
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.long_name = NULL_IF_CONFIG_SMALL("Wing Commander III movie"),
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.priv_data_size = sizeof(Wc3DemuxContext),
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.read_probe = wc3_probe,
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.read_header = wc3_read_header,
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.read_packet = wc3_read_packet,
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.read_close = wc3_read_close,
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};
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