FFmpeg
c93.c
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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 
27 typedef struct C93BlockRecord {
28  uint16_t index;
32 
33 typedef struct C93DemuxContext {
35 
36  C93BlockRecord block_records[512];
38 
39  uint32_t frame_offsets[32];
42 
45 
46 static 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 
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 */
81 
82  video = avformat_new_stream(s, NULL);
83  if (!video)
84  return AVERROR(ENOMEM);
85 
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 
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);
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  ret = AVERROR(EIO);
162  goto fail;
163  }
164 
165  datasize = avio_rl16(pb); /* palette size */
166  if (datasize) {
167  if (datasize != 768) {
168  av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
169  ret = AVERROR_INVALIDDATA;
170  goto fail;
171  }
172  pkt->data[0] |= C93_HAS_PALETTE;
173  ret = avio_read(pb, pkt->data + pkt->size, datasize);
174  if (ret < datasize) {
175  ret = AVERROR(EIO);
176  goto fail;
177  }
178  pkt->size += 768;
179  }
180  pkt->stream_index = 0;
181  c93->next_pkt_is_audio = 1;
182 
183  /* only the first frame is guaranteed to not reference previous frames */
184  if (c93->current_block == 0 && c93->current_frame == 0) {
185  pkt->flags |= AV_PKT_FLAG_KEY;
186  pkt->data[0] |= C93_FIRST_FRAME;
187  }
188  return 0;
189 
190  fail:
191  av_packet_unref(pkt);
192  return ret;
193 }
194 
196  .name = "c93",
197  .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
198  .priv_data_size = sizeof(C93DemuxContext),
199  .read_probe = probe,
202 };
uint32_t frame_offsets[32]
Definition: c93.c:39
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
Definition: voc_packet.c:27
uint8_t frames
Definition: c93.c:30
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4896
static int probe(const AVProbeData *p)
Definition: c93.c:46
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3960
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown)
Definition: avformat.h:943
int size
Definition: avcodec.h:1481
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: c93.c:106
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
static int read_header(AVFormatContext *s)
Definition: c93.c:60
VocDecContext voc
Definition: c93.c:34
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
static AVPacket pkt
int ctx_flags
Flags signalling stream properties.
Definition: avformat.h:1407
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:87
Format I/O context.
Definition: avformat.h:1358
int next_pkt_is_audio
Definition: c93.c:41
uint8_t
int width
Video only.
Definition: avcodec.h:4026
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1302
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4469
int current_frame
Definition: c93.c:40
uint8_t * data
Definition: avcodec.h:1480
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:650
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1512
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define C93_HAS_PALETTE
Definition: c93.c:103
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:772
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3956
#define fail()
Definition: checkasm.h:121
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1486
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:641
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
int current_block
Definition: c93.c:37
#define s(width, name)
Definition: cbs_vp9.c:257
C93BlockRecord block_records[512]
Definition: c93.c:36
Stream structure.
Definition: avformat.h:881
AVStream * audio
Definition: c93.c:43
uint16_t index
Definition: c93.c:28
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
Rational number (pair of numerator and denominator).
Definition: rational.h:58
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:756
Main libavformat public API header.
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:920
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:932
A Quick Description Of Rate Distortion Theory We want to encode a video
AVInputFormat ff_c93_demuxer
Definition: c93.c:195
void * priv_data
Format private data.
Definition: avformat.h:1386
#define C93_FIRST_FRAME
Definition: c93.c:104
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int stream_index
Definition: avcodec.h:1482
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: avcodec.h:1457
uint8_t length
Definition: c93.c:29