254 lines
7.3 KiB
C
254 lines
7.3 KiB
C
/*
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* AVI decoder.
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* Copyright (c) 2001 Gerard Lantau.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "avformat.h"
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#include "avi.h"
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//#define DEBUG
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typedef struct AVIIndex {
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unsigned char tag[4];
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unsigned int flags, pos, len;
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struct AVIIndex *next;
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} AVIIndex;
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typedef struct {
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INT64 movi_end;
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offset_t movi_list;
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AVIIndex *first, *last;
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} AVIContext;
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#ifdef DEBUG
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void print_tag(const char *str, unsigned int tag, int size)
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{
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printf("%s: tag=%c%c%c%c size=0x%x\n",
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str, tag & 0xff,
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(tag >> 8) & 0xff,
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(tag >> 16) & 0xff,
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(tag >> 24) & 0xff,
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size);
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}
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#endif
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int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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AVIContext *avi;
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ByteIOContext *pb = &s->pb;
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UINT32 tag, tag1;
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int codec_type, stream_index, size, frame_period, bit_rate;
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int i, bps;
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AVStream *st;
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avi = malloc(sizeof(AVIContext));
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if (!avi)
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return -1;
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memset(avi, 0, sizeof(AVIContext));
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s->priv_data = avi;
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/* check RIFF header */
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tag = get_le32(pb);
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if (tag != MKTAG('R', 'I', 'F', 'F'))
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return -1;
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get_le32(pb); /* file size */
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tag = get_le32(pb);
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if (tag != MKTAG('A', 'V', 'I', ' '))
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return -1;
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/* first list tag */
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stream_index = -1;
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codec_type = -1;
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frame_period = 0;
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for(;;) {
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if (url_feof(pb))
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goto fail;
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tag = get_le32(pb);
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size = get_le32(pb);
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#ifdef DEBUG
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print_tag("tag", tag, size);
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#endif
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switch(tag) {
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case MKTAG('L', 'I', 'S', 'T'):
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/* ignored, except when start of video packets */
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tag1 = get_le32(pb);
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#ifdef DEBUG
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print_tag("list", tag1, 0);
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#endif
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if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
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avi->movi_end = url_ftell(pb) + size - 4;
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#ifdef DEBUG
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printf("movi end=%Lx\n", avi->movi_end);
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#endif
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goto end_of_header;
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}
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break;
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case MKTAG('a', 'v', 'i', 'h'):
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/* avi header */
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frame_period = get_le32(pb);
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bit_rate = get_le32(pb) * 8;
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url_fskip(pb, 4 * 4);
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s->nb_streams = get_le32(pb);
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for(i=0;i<s->nb_streams;i++) {
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AVStream *st;
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st = malloc(sizeof(AVStream));
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if (!st)
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goto fail;
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memset(st, 0, sizeof(AVStream));
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s->streams[i] = st;
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}
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url_fskip(pb, size - 7 * 4);
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break;
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case MKTAG('s', 't', 'r', 'h'):
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/* stream header */
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stream_index++;
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tag1 = get_le32(pb);
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switch(tag1) {
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case MKTAG('v', 'i', 'd', 's'):
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codec_type = CODEC_TYPE_VIDEO;
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get_le32(pb); /* codec tag */
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get_le32(pb); /* flags */
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get_le16(pb); /* priority */
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get_le16(pb); /* language */
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get_le32(pb); /* XXX: initial frame ? */
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get_le32(pb); /* scale */
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get_le32(pb); /* rate */
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url_fskip(pb, size - 7 * 4);
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break;
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case MKTAG('a', 'u', 'd', 's'):
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codec_type = CODEC_TYPE_AUDIO;
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/* nothing really useful */
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url_fskip(pb, size - 4);
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break;
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default:
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goto fail;
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}
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break;
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case MKTAG('s', 't', 'r', 'f'):
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/* stream header */
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if (stream_index >= s->nb_streams) {
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url_fskip(pb, size);
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} else {
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st = s->streams[stream_index];
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switch(codec_type) {
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case CODEC_TYPE_VIDEO:
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get_le32(pb); /* size */
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st->codec.width = get_le32(pb);
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st->codec.height = get_le32(pb);
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if (frame_period)
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st->codec.frame_rate = (INT64_C(1000000) * FRAME_RATE_BASE) / frame_period;
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else
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st->codec.frame_rate = 25 * FRAME_RATE_BASE;
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get_le16(pb); /* panes */
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get_le16(pb); /* depth */
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tag1 = get_le32(pb);
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#ifdef DEBUG
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print_tag("video", tag1, 0);
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#endif
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st->codec.codec_type = CODEC_TYPE_VIDEO;
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st->codec.codec_tag = tag1;
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st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
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url_fskip(pb, size - 5 * 4);
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break;
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case CODEC_TYPE_AUDIO:
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tag1 = get_le16(pb);
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st->codec.codec_type = CODEC_TYPE_AUDIO;
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st->codec.codec_tag = tag1;
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#ifdef DEBUG
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printf("audio: 0x%x\n", tag1);
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#endif
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st->codec.channels = get_le16(pb);
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st->codec.sample_rate = get_le32(pb);
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st->codec.bit_rate = get_le32(pb) * 8;
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get_le16(pb); /* block align */
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bps = get_le16(pb);
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st->codec.codec_id = wav_codec_get_id(tag1, bps);
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url_fskip(pb, size - 4 * 4);
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break;
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default:
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url_fskip(pb, size);
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break;
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}
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}
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break;
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default:
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/* skip tag */
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size += (size & 1);
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url_fskip(pb, size);
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break;
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}
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}
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end_of_header:
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/* check stream number */
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if (stream_index != s->nb_streams - 1) {
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fail:
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for(i=0;i<s->nb_streams;i++) {
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if (s->streams[i])
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free(s->streams[i]);
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}
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return -1;
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}
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return 0;
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}
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int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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AVIContext *avi = s->priv_data;
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ByteIOContext *pb = &s->pb;
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int n, d1, d2, size;
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find_next:
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if (url_feof(pb) || url_ftell(pb) >= avi->movi_end)
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return -1;
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d1 = get_byte(pb);
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if (d1 < '0' || d1 > '9')
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goto find_next;
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d2 = get_byte(pb);
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if (d2 < '0' || d2 > '9')
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goto find_next;
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n = (d1 - '0') * 10 + (d2 - '0');
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if (n < 0 || n >= s->nb_streams)
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goto find_next;
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d1 = get_byte(pb);
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d2 = get_byte(pb);
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if ((d1 != 'd' && d2 != 'c') &&
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(d1 != 'w' && d2 != 'b'))
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goto find_next;
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size = get_le32(pb);
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av_new_packet(pkt, size);
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pkt->stream_index = n;
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get_buffer(pb, pkt->data, pkt->size);
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if (size & 1)
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get_byte(pb);
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return 0;
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}
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int avi_read_close(AVFormatContext *s)
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{
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AVIContext *avi = s->priv_data;
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free(avi);
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return 0;
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}
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