FFmpeg
lmlm4.c
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1 /*
2  * Linux Media Labs MPEG-4 demuxer
3  * Copyright (c) 2008 Ivo van Poorten
4  *
5  * Due to a lack of sample files, only files with one channel are supported.
6  * u-law and ADPCM audio are unsupported for the same reason.
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "libavutil/intreadwrite.h"
26 
27 #include "avformat.h"
28 #include "internal.h"
29 
30 #define LMLM4_I_FRAME 0x00
31 #define LMLM4_P_FRAME 0x01
32 #define LMLM4_B_FRAME 0x02
33 #define LMLM4_INVALID 0x03
34 #define LMLM4_MPEG1L2 0x04
35 
36 #define LMLM4_MAX_PACKET_SIZE 1024 * 1024
37 
38 static int lmlm4_probe(const AVProbeData *pd)
39 {
40  const unsigned char *buf = pd->buf;
41  unsigned int frame_type, packet_size;
42 
43  frame_type = AV_RB16(buf + 2);
44  packet_size = AV_RB32(buf + 4);
45 
46  if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
47  frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
48  if (frame_type == LMLM4_MPEG1L2) {
49  if ((AV_RB16(buf + 8) & 0xfffe) != 0xfffc)
50  return 0;
51  /* I could calculate the audio framesize and compare with
52  * packet_size-8, but that seems overkill */
53  return AVPROBE_SCORE_MAX / 3;
54  } else if (AV_RB24(buf + 8) == 0x000001) { /* PES Signal */
55  return AVPROBE_SCORE_MAX / 5;
56  }
57  }
58 
59  return 0;
60 }
61 
63 {
64  AVStream *st;
65 
66  if (!(st = avformat_new_stream(s, NULL)))
67  return AVERROR(ENOMEM);
71  avpriv_set_pts_info(st, 64, 1001, 30000);
72 
73  if (!(st = avformat_new_stream(s, NULL)))
74  return AVERROR(ENOMEM);
78 
79  /* the parameters will be extracted from the compressed bitstream */
80  return 0;
81 }
82 
84 {
85  AVIOContext *pb = s->pb;
86  int ret;
87  unsigned int frame_type, packet_size, padding, frame_size;
88 
89  avio_rb16(pb); /* channel number */
90  frame_type = avio_rb16(pb);
91  packet_size = avio_rb32(pb);
92  padding = -packet_size & 511;
93  frame_size = packet_size - 8;
94 
95  if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
96  av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
97  return AVERROR(EIO);
98  }
99  if (packet_size > LMLM4_MAX_PACKET_SIZE || packet_size<=8) {
100  av_log(s, AV_LOG_ERROR, "packet size %d is invalid\n", packet_size);
101  return AVERROR(EIO);
102  }
103 
104  if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
105  return AVERROR(EIO);
106 
107  avio_skip(pb, padding);
108 
109  switch (frame_type) {
110  case LMLM4_I_FRAME:
111  pkt->flags = AV_PKT_FLAG_KEY;
112  case LMLM4_P_FRAME:
113  case LMLM4_B_FRAME:
114  pkt->stream_index = 0;
115  break;
116  case LMLM4_MPEG1L2:
117  pkt->stream_index = 1;
118  break;
119  }
120 
121  return ret;
122 }
123 
125  .name = "lmlm4",
126  .long_name = NULL_IF_CONFIG_SMALL("raw lmlm4"),
127  .read_probe = lmlm4_probe,
128  .read_header = lmlm4_read_header,
129  .read_packet = lmlm4_read_packet,
130 };
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define LMLM4_P_FRAME
Definition: lmlm4.c:31
AVInputFormat ff_lmlm4_demuxer
Definition: lmlm4.c:124
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:4929
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3968
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:788
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
Format I/O context.
Definition: avformat.h:1358
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:803
static int lmlm4_read_header(AVFormatContext *s)
Definition: lmlm4.c:62
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4502
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:87
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
#define LMLM4_I_FRAME
Definition: lmlm4.c:30
#define av_log(a,...)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1512
#define LMLM4_MPEG1L2
Definition: lmlm4.c:34
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
#define LMLM4_MAX_PACKET_SIZE
Definition: lmlm4.c:36
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3964
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1486
Only parse headers, do not repack.
Definition: avformat.h:801
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define s(width, name)
Definition: cbs_vp9.c:257
static int lmlm4_probe(const AVProbeData *pd)
Definition: lmlm4.c:38
#define LMLM4_B_FRAME
Definition: lmlm4.c:32
Stream structure.
Definition: avformat.h:881
int frame_size
Definition: mxfenc.c:2214
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:87
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
#define LMLM4_INVALID
Definition: lmlm4.c:33
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: lmlm4.c:83
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