diff options
Diffstat (limited to 'libavformat/avidec.c')
| -rw-r--r-- | libavformat/avidec.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/libavformat/avidec.c b/libavformat/avidec.c new file mode 100644 index 0000000000..9646408cd1 --- /dev/null +++ b/libavformat/avidec.c @@ -0,0 +1,256 @@ +/* + * AVI decoder. + * Copyright (c) 2001 Fabrice Bellard. + * + * This library 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 of the License, or (at your option) any later version. + * + * This library 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 this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include "avformat.h" +#include "avi.h" + +//#define DEBUG + +typedef struct AVIIndex { + unsigned char tag[4]; + unsigned int flags, pos, len; + struct AVIIndex *next; +} AVIIndex; + +typedef struct { + INT64 movi_end; + offset_t movi_list; + AVIIndex *first, *last; +} AVIContext; + +#ifdef DEBUG +static void print_tag(const char *str, unsigned int tag, int size) +{ + printf("%s: tag=%c%c%c%c size=0x%x\n", + str, tag & 0xff, + (tag >> 8) & 0xff, + (tag >> 16) & 0xff, + (tag >> 24) & 0xff, + size); +} +#endif + +static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap) +{ + AVIContext *avi = s->priv_data; + ByteIOContext *pb = &s->pb; + UINT32 tag, tag1; + int codec_type, stream_index, size, frame_period, bit_rate; + int i; + AVStream *st; + + /* check RIFF header */ + tag = get_le32(pb); + + if (tag != MKTAG('R', 'I', 'F', 'F')) + return -1; + get_le32(pb); /* file size */ + tag = get_le32(pb); + if (tag != MKTAG('A', 'V', 'I', ' ')) + return -1; + + /* first list tag */ + stream_index = -1; + codec_type = -1; + frame_period = 0; + for(;;) { + if (url_feof(pb)) + goto fail; + tag = get_le32(pb); + size = get_le32(pb); +#ifdef DEBUG + print_tag("tag", tag, size); +#endif + + switch(tag) { + case MKTAG('L', 'I', 'S', 'T'): + /* ignored, except when start of video packets */ + tag1 = get_le32(pb); +#ifdef DEBUG + print_tag("list", tag1, 0); +#endif + if (tag1 == MKTAG('m', 'o', 'v', 'i')) { + avi->movi_end = url_ftell(pb) + size - 4; +#ifdef DEBUG + printf("movi end=%Lx\n", avi->movi_end); +#endif + goto end_of_header; + } + break; + case MKTAG('a', 'v', 'i', 'h'): + /* avi header */ + /* using frame_period is bad idea */ + frame_period = get_le32(pb); + bit_rate = get_le32(pb) * 8; + url_fskip(pb, 4 * 4); + s->nb_streams = get_le32(pb); + for(i=0;i<s->nb_streams;i++) { + AVStream *st = av_mallocz(sizeof(AVStream)); + if (!st) + goto fail; + s->streams[i] = st; + } + url_fskip(pb, size - 7 * 4); + break; + case MKTAG('s', 't', 'r', 'h'): + /* stream header */ + stream_index++; + tag1 = get_le32(pb); + switch(tag1) { + case MKTAG('v', 'i', 'd', 's'): + codec_type = CODEC_TYPE_VIDEO; + get_le32(pb); /* codec tag */ + get_le32(pb); /* flags */ + get_le16(pb); /* priority */ + get_le16(pb); /* language */ + get_le32(pb); /* XXX: initial frame ? */ + get_le32(pb); /* scale */ + get_le32(pb); /* rate */ + size -= 6 * 4; + break; + case MKTAG('a', 'u', 'd', 's'): + codec_type = CODEC_TYPE_AUDIO; + /* nothing really useful */ + } + url_fskip(pb, size - 4); + break; + case MKTAG('s', 't', 'r', 'f'): + /* stream header */ + if (stream_index >= s->nb_streams) { + url_fskip(pb, size); + } else { + st = s->streams[stream_index]; + switch(codec_type) { + case CODEC_TYPE_VIDEO: + get_le32(pb); /* size */ + st->codec.width = get_le32(pb); + st->codec.height = get_le32(pb); + if (frame_period) + st->codec.frame_rate = (INT64_C(1000000) * FRAME_RATE_BASE) / frame_period; + else + st->codec.frame_rate = 25 * FRAME_RATE_BASE; + get_le16(pb); /* panes */ + get_le16(pb); /* depth */ + tag1 = get_le32(pb); +#ifdef DEBUG + print_tag("video", tag1, 0); +#endif + st->codec.codec_type = CODEC_TYPE_VIDEO; + st->codec.codec_tag = tag1; + st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1); + url_fskip(pb, size - 5 * 4); + break; + case CODEC_TYPE_AUDIO: + get_wav_header(pb, &st->codec, (size >= 18)); + break; + default: + url_fskip(pb, size); + break; + } + } + break; + default: + /* skip tag */ + size += (size & 1); + url_fskip(pb, size); + break; + } + } + end_of_header: + /* check stream number */ + if (stream_index != s->nb_streams - 1) { + fail: + for(i=0;i<s->nb_streams;i++) { + av_freep(&s->streams[i]); + } + return -1; + } + + return 0; +} + +static int avi_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + AVIContext *avi = s->priv_data; + ByteIOContext *pb = &s->pb; + int n, d1, d2, size; + + for(;;) { + if (url_feof(pb) || url_ftell(pb) >= avi->movi_end) + return -1; + d1 = get_byte(pb) - '0'; + d2 = get_byte(pb) - '0'; + if (d1 < 0 || d1 > 9 || d2 < 0 || d2 > 9) + continue; + + n = d1 * 10 + d2; + if (n < 0 || n >= s->nb_streams) + continue; + + d1 = get_byte(pb); + d2 = get_byte(pb); + if ((d1 == 'd' && d2 == 'c') + || (d1 == 'w' && d2 == 'b')) + break; + } + size = get_le32(pb); + av_new_packet(pkt, size); + pkt->stream_index = n; + + get_buffer(pb, pkt->data, pkt->size); + + if (size & 1) + get_byte(pb); + + return 0; +} + +static int avi_read_close(AVFormatContext *s) +{ + return 0; +} + +static int avi_probe(AVProbeData *p) +{ + /* check file header */ + if (p->buf_size <= 32) + return 0; + if (p->buf[0] == 'R' && p->buf[1] == 'I' && + p->buf[2] == 'F' && p->buf[3] == 'F' && + p->buf[8] == 'A' && p->buf[9] == 'V' && + p->buf[10] == 'I' && p->buf[11] == ' ') + return AVPROBE_SCORE_MAX; + else + return 0; +} + +static AVInputFormat avi_iformat = { + "avi", + "avi format", + sizeof(AVIContext), + avi_probe, + avi_read_header, + avi_read_packet, + avi_read_close, +}; + +int avidec_init(void) +{ + av_register_input_format(&avi_iformat); + return 0; +} |