相关文章推荐
文武双全的企鹅  ·  学而优则仕又一例：扬州大学党委书记夏锦文拟任 ...·  10 月前    · 
心软的铁板烧  ·  生成文件中的命令 | Microsoft ...·  1 年前    · 
腼腆的拖把  ·  .net core RSA ...·  2 年前    · 
酒量小的骆驼  ·  快来嘛欢迎敬水龙乐园3_头条·  2 年前    · 
聪明的鞭炮  ·  大家平时用什么网站找电子书？ - 知乎·  2 年前    · 
Code  ›  vs2017调用目标发生异常_visual studio 2017调用的目标发生了异常
编辑器 变量 wtl
https://blog.csdn.net/y1535623813/article/details/87930292
成熟的烤地瓜
1 年前
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public License
8 * as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
21 #include " libavutil/avassert.h "
22 #include " libavutil/avstring.h "
23 #include " libavutil/opt.h "
24 #include " avformat.h "
25 #include " url.h "
27 typedef struct SubfileContext {
28 const AVClass * class ;
29 URLContext * h ;
30 int64_t start ;
31 int64_t end ;
32 int64_t pos ;
33 } SubfileContext ;
35 #define OFFSET(field) offsetof(SubfileContext, field)
36 #define D AV_OPT_FLAG_DECODING_PARAM
38 static const AVOption subfile_options [] = {
39 { "start" , "start offset" , OFFSET ( start ), AV_OPT_TYPE_INT64 , {.i64 = 0}, 0, INT64_MAX, D },
40 { "end" , "end offset" , OFFSET ( end ), AV_OPT_TYPE_INT64 , {.i64 = 0}, 0, INT64_MAX, D },
41 { NULL }
42 };
44 #undef OFFSET
45 #undef D
47 static const AVClass subfile_class = {
48 . class_name = "subfile" ,
49 .item_name = av_default_item_name ,
50 .option = subfile_options ,
51 .version = LIBAVUTIL_VERSION_INT ,
52 };
54 static int slave_seek ( URLContext * h )
55 {
56 SubfileContext * c = h-> priv_data ;
57 int64_t ret;
59 if ((ret = ffurl_seek (c-> h , c-> pos , SEEK_SET)) != c-> pos ) {
60 if (ret >= 0)
61 ret = AVERROR_BUG ;
62 av_log (h, AV_LOG_ERROR , "Impossible to seek in file: %s\n" ,
63 av_err2str (ret));
64 return ret;
65 }
66 return 0;
67 }
69 static int subfile_open ( URLContext * h , const char *filename, int flags ,
70 AVDictionary ** options )
71 {
72 SubfileContext * c = h-> priv_data ;
73 int ret;
75 if (c-> end <= c-> start ) {
76 av_log (h, AV_LOG_ERROR , "end before start\n" );
77 return AVERROR (EINVAL);
78 }
79 av_strstart (filename, "subfile:" , &filename);
80 ret = ffurl_open (&c-> h , filename, flags, &h-> interrupt_callback , options);
81 if (ret < 0)
82 return ret;
83 c-> pos = c-> start ;
84 if ((ret = slave_seek (h)) < 0) {
85 ffurl_close (c-> h );
86 return ret;
87 }
88 return 0;
89 }
91 static int subfile_close ( URLContext * h )
92 {
93 SubfileContext * c = h-> priv_data ;
94 return ffurl_close (c-> h );
95 }
97 static int subfile_read ( URLContext * h , unsigned char * buf , int size )
98 {
99 SubfileContext * c = h-> priv_data ;
100 int64_t rest = c-> end - c-> pos ;
101 int ret;
103 if (rest <= 0)
104 return 0;
105 size = FFMIN (size, rest);
106 ret = ffurl_read (c-> h , buf, size);
107 if (ret >= 0)
108 c-> pos += ret;
109 return ret;
110 }
112 static int64_t subfile_seek ( URLContext * h , int64_t pos, int whence)
113 {
114 SubfileContext * c = h-> priv_data ;
115 int64_t new_pos = -1;
116 int ret;
118 if (whence == AVSEEK_SIZE )
119 return c-> end - c-> start ;
120 switch (whence) {
121 case SEEK_SET:
122 new_pos = c-> start + pos;
123 break ;
124 case SEEK_CUR:
125 new_pos += pos;
126 break ;
127 case SEEK_END:
128 new_pos = c-> end + c-> pos ;
129 break ;
130 }
131 if (new_pos < c-> start )
132 return AVERROR (EINVAL);
133 c-> pos = new_pos;
134 if ((ret = slave_seek (h)) < 0)
135 return ret;
136 return c-> pos - c-> start ;
137 }
139 URLProtocol ff_subfile_protocol = {
140 . name = "subfile" ,
141 .url_open2 = subfile_open ,
142 .url_read = subfile_read ,
143 .url_seek = subfile_seek ,
144 .url_close = subfile_close ,
145 .priv_data_size = sizeof ( SubfileContext ),
146 .priv_data_class = &subfile_class,
147 };
slave_seek
static int slave_seek(URLContext *h)
Definition: subfile.c:54
NULL
#define NULL
Definition: coverity.c:32
AV_OPT_TYPE_INT64
Definition: opt.h:224
h
h
Definition: vp9dsp_template.c:2093
AVOption
AVOption.
Definition: opt.h:255
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:62
URLContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Definition: url.h:48
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
opt.h
AVOptions.
end
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
ff_subfile_protocol
URLProtocol ff_subfile_protocol
Definition: subfile.c:139
size
ptrdiff_t size
Definition: opengl_enc.c:101
options
const OptionDef options[]
Definition: ffserver.c:3807
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
subfile_options
static const AVOption subfile_options[]
Definition: subfile.c:38
subfile_read
static int subfile_read(URLContext *h, unsigned char *buf, int size)
Definition: subfile.c:97
av_default_item_name
av_default_item_name
Definition: libopenh264enc.c:59
AVERROR
#define AVERROR(e)
Definition: error.h:43
avassert.h
simple assert() macros that are a bit more flexible than ISO C assert().
SubfileContext::start
int64_t start
Definition: subfile.c:30
FFMIN
#define FFMIN(a, b)
Definition: common.h:81
av_err2str
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
subfile_open
static int subfile_open(URLContext *h, const char *filename, int flags, AVDictionary **options)
Definition: subfile.c:69
SubfileContext::h
URLContext * h
Definition: subfile.c:29
buf
void * buf
Definition: avisynth_c.h:553
AVERROR_BUG
#define AVERROR_BUG
Internal bug, also see AVERROR_BUG2.
Definition: error.h:50
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
URLContext::priv_data
void * priv_data
Definition: url.h:42
OFFSET
#define OFFSET(field)
Definition: subfile.c:35
D
#define D
Definition: subfile.c:36
URLProtocol::name
const char * name
Definition: url.h:53
flags
static int flags
Definition: cpu.c:47
ffurl_close
int ffurl_close(URLContext *h)
Definition: avio.c:412
subfile_seek
static int64_t subfile_seek(URLContext *h, int64_t pos, int whence)
Definition: subfile.c:112
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
avformat.h
Main libavformat public API header.
ffurl_seek
int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
Change the position that will be used by the next read/write operation on the resource accessed by h...
Definition: avio.c:380
ffurl_open
int ffurl_open(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:292
subfile_close
static int subfile_close(URLContext *h)
Definition: subfile.c:91
c
static double c[64]
Definition: vsrc_mptestsrc.c:87
AVSEEK_SIZE
#define AVSEEK_SIZE
Passing this as the "whence" parameter to a seek function causes it to return the filesize without se...
Definition: avio.h:364
start
void INT64 start
Definition: avisynth_c.h:553
url.h
unbuffered private I/O API
subfile_class
static const AVClass subfile_class
Definition: subfile.c:47
ffurl_read
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf...
Definition: avio.c:353
 
推荐文章
文武双全的企鹅  ·  学而优则仕又一例：扬州大学党委书记夏锦文拟任镇江市委书记_长三角政商_澎湃新闻-The Paper
10 月前
心软的铁板烧  ·  生成文件中的命令 | Microsoft Learn
1 年前
腼腆的拖把  ·  .net core RSA 分段加密解密，签名验签（对接java） - caolingyi - 博客园
2 年前
酒量小的骆驼  ·  快来嘛欢迎敬水龙乐园3_头条
2 年前
聪明的鞭炮  ·  大家平时用什么网站找电子书？ - 知乎
2 年前
今天看啥   ·   Py中国   ·   codingpro   ·   小百科   ·   link之家   ·   卧龙AI搜索
删除内容请联系邮箱 2879853325@qq.com
Code - 代码工具平台
© 2024 ~ 沪ICP备11025650号