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;
29  uint8_t length;
30  uint8_t frames;
32 
33 typedef struct C93DemuxContext {
34  VocDecContext voc;
35 
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 */
80  s->ctx_flags |= AVFMTCTX_NOHEADER;
81 
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 
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;
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) {
183  pkt->data[0] |= C93_FIRST_FRAME;
184  }
185  return 0;
186 }
187 
189  .name = "c93",
190  .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
191  .priv_data_size = sizeof(C93DemuxContext),
192  .read_probe = probe,
195 };
C93DemuxContext::next_pkt_is_audio
int next_pkt_is_audio
Definition: c93.c:41
AVERROR
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:760
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
C93BlockRecord::frames
uint8_t frames
Definition: c93.c:30
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
read_packet
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: c93.c:106
index
fg index
Definition: ffmpeg_filter.c:165
AVPacket::data
uint8_t * data
Definition: packet.h:373
C93DemuxContext::voc
VocDecContext voc
Definition: c93.c:34
ff_c93_demuxer
const AVInputFormat ff_c93_demuxer
Definition: c93.c:188
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:450
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:425
read_header
static int read_header(AVFormatContext *s)
Definition: c93.c:60
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:459
C93_FIRST_FRAME
#define C93_FIRST_FRAME
Definition: c93.c:104
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:743
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
AVInputFormat
Definition: avformat.h:643
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:99
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:648
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:449
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
C93BlockRecord::length
uint8_t length
Definition: c93.c:29
C93DemuxContext::block_records
C93BlockRecord block_records[512]
Definition: c93.c:36
AVFormatContext
Format I/O context.
Definition: avformat.h:1193
internal.h
C93DemuxContext::current_frame
int current_frame
Definition: c93.c:40
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1088
C93BlockRecord
Definition: c93.c:27
NULL
#define NULL
Definition: coverity.c:32
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVFMTCTX_NOHEADER
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1144
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:447
C93_HAS_PALETTE
#define C93_HAS_PALETTE
Definition: c93.c:103
C93DemuxContext::current_block
int current_block
Definition: c93.c:37
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
C93DemuxContext::audio
AVStream * audio
Definition: c93.c:43
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:632
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:379
voc.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
ff_voc_get_packet
int ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
Definition: voc_packet.c:27
AV_CODEC_ID_C93
@ AV_CODEC_ID_C93
Definition: codec_id.h:152
C93DemuxContext
Definition: c93.c:33
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:928
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
avformat.h
video
A Quick Description Of Rate Distortion Theory We want to encode a video
Definition: rate_distortion.txt:3
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:641
probe
static int probe(const AVProbeData *p)
Definition: c93.c:46
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, 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:1186
AVPacket::stream_index
int stream_index
Definition: packet.h:375
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
C93DemuxContext::frame_offsets
uint32_t frame_offsets[32]
Definition: c93.c:39
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVPacket
This structure stores compressed data.
Definition: packet.h:350
C93BlockRecord::index
uint16_t index
Definition: c93.c:28
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61