FFmpeg: libavformat/c93.c Source File

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;
31 } C93BlockRecord;
32 
33  typedef 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 
46  static int probe(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 
60  static 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 
106  static 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  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 
195  AVInputFormat ff_c93_demuxer = {
196  .name = "c93",
197  .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
198  .priv_data_size = sizeof(C93DemuxContext),
199  .read_probe = probe,
200  .read_header = read_header,
201  .read_packet = read_packet,
202 };
C93DemuxContext::frame_offsets
uint32_t frame_offsets[32]
Definition: c93.c:39
NULL
#define NULL
Definition: coverity.c:32
probe
static int probe(AVProbeData *p)
Definition: c93.c:46
s
const char * s
Definition: avisynth_c.h:768
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ff_voc_get_packet
int ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
Definition: voc_packet.c:27
C93BlockRecord::frames
uint8_t frames
Definition: c93.c:30
avpriv_set_pts_info
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:4737
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:4152
AVStream::sample_aspect_ratio
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown)
Definition: avformat.h:959
AVPacket::size
int size
Definition: avcodec.h:1680
read_packet
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: c93.c:106
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:244
read_header
static int read_header(AVFormatContext *s)
Definition: c93.c:60
C93DemuxContext::voc
VocDecContext voc
Definition: c93.c:34
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:329
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
AVFormatContext::ctx_flags
int ctx_flags
Flags signalling stream properties.
Definition: avformat.h:1398
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:87
AVFormatContext
Format I/O context.
Definition: avformat.h:1349
C93DemuxContext::next_pkt_is_audio
int next_pkt_is_audio
Definition: c93.c:41
uint8_t
uint8_t
Definition: audio_convert.c:194
AVCodecParameters::width
int width
Video only.
Definition: avcodec.h:4218
AVFMTCTX_NOHEADER
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1302
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4367
C93DemuxContext::current_frame
int current_frame
Definition: c93.c:40
AVPacket::data
uint8_t * data
Definition: avcodec.h:1679
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:637
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1711
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:86
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
C93_HAS_PALETTE
#define C93_HAS_PALETTE
Definition: c93.c:103
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
AVERROR
#define AVERROR(e)
Definition: error.h:43
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:179
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:4148
AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
VocDecContext
Definition: voc.h:28
fail
#define fail()
Definition: checkasm.h:109
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1685
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:464
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:463
read_probe
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
C93DemuxContext::current_block
int current_block
Definition: c93.c:37
C93DemuxContext::block_records
C93BlockRecord block_records[512]
Definition: c93.c:36
AVStream
Stream structure.
Definition: avformat.h:889
C93DemuxContext::audio
AVStream * audio
Definition: c93.c:43
C93BlockRecord::index
uint16_t index
Definition: c93.c:28
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1391
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:618
index
int index
Definition: gxfenc.c:89
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:461
AV_CODEC_ID_C93
Definition: avcodec.h:322
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:946
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:473
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:743
avformat.h
Main libavformat public API header.
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:936
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:948
ff_c93_demuxer
AVInputFormat ff_c93_demuxer
Definition: c93.c:195
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1377
C93_FIRST_FRAME
#define C93_FIRST_FRAME
Definition: c93.c:104
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:664
AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVStream::codecpar
AVCodecParameters * codecpar
Definition: avformat.h:1252
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1681
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1656
C93BlockRecord::length
uint8_t length
Definition: c93.c:29
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