PageRenderTime 47ms CodeModel.GetById 20ms app.highlight 22ms RepoModel.GetById 1ms app.codeStats 0ms

/libavformat/c93.c

http://github.com/FFmpeg/FFmpeg
C | 195 lines | 149 code | 23 blank | 23 comment | 30 complexity | 1bc66e16a1ecd4bab14114205aed23c9 MD5 | raw file
  1/*
  2 * Interplay C93 demuxer
  3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
  4 *
  5 * This file is part of FFmpeg.
  6 *
  7 * FFmpeg is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU Lesser General Public
  9 * License as published by the Free Software Foundation; either
 10 * version 2.1 of the License, or (at your option) any later version.
 11 *
 12 * FFmpeg is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 15 * Lesser General Public License for more details.
 16 *
 17 * You should have received a copy of the GNU Lesser General Public
 18 * License along with FFmpeg; if not, write to the Free Software
 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 20 */
 21
 22#include "avformat.h"
 23#include "internal.h"
 24#include "voc.h"
 25#include "libavutil/intreadwrite.h"
 26
 27typedef struct C93BlockRecord {
 28    uint16_t index;
 29    uint8_t length;
 30    uint8_t frames;
 31} C93BlockRecord;
 32
 33typedef struct C93DemuxContext {
 34    VocDecContext voc;
 35
 36    C93BlockRecord block_records[512];
 37    int current_block;
 38
 39    uint32_t frame_offsets[32];
 40    int current_frame;
 41    int next_pkt_is_audio;
 42
 43    AVStream *audio;
 44} C93DemuxContext;
 45
 46static int probe(const AVProbeData *p)
 47{
 48    int i;
 49    int index = 1;
 50    if (p->buf_size < 16)
 51        return 0;
 52    for (i = 0; i < 16; i += 4) {
 53        if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])
 54            return 0;
 55        index += p->buf[i + 2];
 56    }
 57    return AVPROBE_SCORE_MAX;
 58}
 59
 60static int read_header(AVFormatContext *s)
 61{
 62    AVStream *video;
 63    AVIOContext *pb = s->pb;
 64    C93DemuxContext *c93 = s->priv_data;
 65    int i;
 66    int framecount = 0;
 67
 68    for (i = 0; i < 512; i++) {
 69        c93->block_records[i].index = avio_rl16(pb);
 70        c93->block_records[i].length = avio_r8(pb);
 71        c93->block_records[i].frames = avio_r8(pb);
 72        if (c93->block_records[i].frames > 32) {
 73            av_log(s, AV_LOG_ERROR, "too many frames in block\n");
 74            return AVERROR_INVALIDDATA;
 75        }
 76        framecount += c93->block_records[i].frames;
 77    }
 78
 79    /* Audio streams are added if audio packets are found */
 80    s->ctx_flags |= AVFMTCTX_NOHEADER;
 81
 82    video = avformat_new_stream(s, NULL);
 83    if (!video)
 84        return AVERROR(ENOMEM);
 85
 86    video->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 87    video->codecpar->codec_id = AV_CODEC_ID_C93;
 88    video->codecpar->width = 320;
 89    video->codecpar->height = 192;
 90    /* 4:3 320x200 with 8 empty lines */
 91    video->sample_aspect_ratio = (AVRational) { 5, 6 };
 92    avpriv_set_pts_info(video, 64, 2, 25);
 93    video->nb_frames = framecount;
 94    video->duration = framecount;
 95    video->start_time = 0;
 96
 97    c93->current_block = 0;
 98    c93->current_frame = 0;
 99    c93->next_pkt_is_audio = 0;
100    return 0;
101}
102
103#define C93_HAS_PALETTE 0x01
104#define C93_FIRST_FRAME 0x02
105
106static int read_packet(AVFormatContext *s, AVPacket *pkt)
107{
108    AVIOContext *pb = s->pb;
109    C93DemuxContext *c93 = s->priv_data;
110    C93BlockRecord *br = &c93->block_records[c93->current_block];
111    int datasize;
112    int ret, i;
113
114    if (c93->next_pkt_is_audio) {
115        c93->current_frame++;
116        c93->next_pkt_is_audio = 0;
117        datasize = avio_rl16(pb);
118        if (datasize > 42) {
119            if (!c93->audio) {
120                c93->audio = avformat_new_stream(s, NULL);
121                if (!c93->audio)
122                    return AVERROR(ENOMEM);
123                c93->audio->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
124            }
125            avio_skip(pb, 26); /* VOC header */
126            ret = ff_voc_get_packet(s, pkt, c93->audio, datasize - 26);
127            if (ret > 0) {
128                pkt->stream_index = 1;
129                pkt->flags |= AV_PKT_FLAG_KEY;
130                return ret;
131            }
132        }
133    }
134    if (c93->current_frame >= br->frames) {
135        if (c93->current_block >= 511 || !br[1].length)
136            return AVERROR_EOF;
137        br++;
138        c93->current_block++;
139        c93->current_frame = 0;
140    }
141
142    if (c93->current_frame == 0) {
143        avio_seek(pb, br->index * 2048, SEEK_SET);
144        for (i = 0; i < 32; i++) {
145            c93->frame_offsets[i] = avio_rl32(pb);
146        }
147    }
148
149    avio_seek(pb,br->index * 2048 +
150            c93->frame_offsets[c93->current_frame], SEEK_SET);
151    datasize = avio_rl16(pb); /* video frame size */
152
153    ret = av_new_packet(pkt, datasize + 768 + 1);
154    if (ret < 0)
155        return ret;
156    pkt->data[0] = 0;
157    pkt->size = datasize + 1;
158
159    ret = avio_read(pb, pkt->data + 1, datasize);
160    if (ret < datasize) {
161        return AVERROR(EIO);
162    }
163
164    datasize = avio_rl16(pb); /* palette size */
165    if (datasize) {
166        if (datasize != 768) {
167            av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
168            return AVERROR_INVALIDDATA;
169        }
170        pkt->data[0] |= C93_HAS_PALETTE;
171        ret = avio_read(pb, pkt->data + pkt->size, datasize);
172        if (ret < datasize) {
173            return AVERROR(EIO);
174        }
175        pkt->size += 768;
176    }
177    pkt->stream_index = 0;
178    c93->next_pkt_is_audio = 1;
179
180    /* only the first frame is guaranteed to not reference previous frames */
181    if (c93->current_block == 0 && c93->current_frame == 0) {
182        pkt->flags |= AV_PKT_FLAG_KEY;
183        pkt->data[0] |= C93_FIRST_FRAME;
184    }
185    return 0;
186}
187
188AVInputFormat ff_c93_demuxer = {
189    .name           = "c93",
190    .long_name      = NULL_IF_CONFIG_SMALL("Interplay C93"),
191    .priv_data_size = sizeof(C93DemuxContext),
192    .read_probe     = probe,
193    .read_header    = read_header,
194    .read_packet    = read_packet,
195};