Statistics
| Branch: | Revision:

ffmpeg / doc / demuxers.texi @ bebe72f4

History | View | Annotate | Download (2.95 KB)

1
@chapter Demuxers
2
@c man begin DEMUXERS
3

    
4
Demuxers are configured elements in Libav which allow to read the
5
multimedia streams from a particular type of file.
6

    
7
When you configure your Libav build, all the supported demuxers
8
are enabled by default. You can list all available ones using the
9
configure option "--list-demuxers".
10

    
11
You can disable all the demuxers using the configure option
12
"--disable-demuxers", and selectively enable a single demuxer with
13
the option "--enable-demuxer=@var{DEMUXER}", or disable it
14
with the option "--disable-demuxer=@var{DEMUXER}".
15

    
16
The option "-formats" of the ff* tools will display the list of
17
enabled demuxers.
18

    
19
The description of some of the currently available demuxers follows.
20

    
21
@section image2
22

    
23
Image file demuxer.
24

    
25
This demuxer reads from a list of image files specified by a pattern.
26

    
27
The pattern may contain the string "%d" or "%0@var{N}d", which
28
specifies the position of the characters representing a sequential
29
number in each filename matched by the pattern. If the form
30
"%d0@var{N}d" is used, the string representing the number in each
31
filename is 0-padded and @var{N} is the total number of 0-padded
32
digits representing the number. The literal character '%' can be
33
specified in the pattern with the string "%%".
34

    
35
If the pattern contains "%d" or "%0@var{N}d", the first filename of
36
the file list specified by the pattern must contain a number
37
inclusively contained between 0 and 4, all the following numbers must
38
be sequential. This limitation may be hopefully fixed.
39

    
40
The pattern may contain a suffix which is used to automatically
41
determine the format of the images contained in the files.
42

    
43
For example the pattern "img-%03d.bmp" will match a sequence of
44
filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
45
@file{img-010.bmp}, etc.; the pattern "i%%m%%g-%d.jpg" will match a
46
sequence of filenames of the form @file{i%m%g-1.jpg},
47
@file{i%m%g-2.jpg}, ..., @file{i%m%g-10.jpg}, etc.
48

    
49
The size, the pixel format, and the format of each image must be the
50
same for all the files in the sequence.
51

    
52
The following example shows how to use @file{ffmpeg} for creating a
53
video from the images in the file sequence @file{img-001.jpeg},
54
@file{img-002.jpeg}, ..., assuming an input framerate of 10 frames per
55
second:
56
@example
57
ffmpeg -r 10 -f image2 -i 'img-%03d.jpeg' out.avi
58
@end example
59

    
60
Note that the pattern must not necessarily contain "%d" or
61
"%0@var{N}d", for example to convert a single image file
62
@file{img.jpeg} you can employ the command:
63
@example
64
ffmpeg -f image2 -i img.jpeg img.png
65
@end example
66

    
67
@section applehttp
68

    
69
Apple HTTP Live Streaming demuxer.
70

    
71
This demuxer presents all AVStreams from all variant streams.
72
The id field is set to the bitrate variant index number. By setting
73
the discard flags on AVStreams (by pressing 'a' or 'v' in ffplay),
74
the caller can decide which variant streams to actually receive.
75
The total bitrate of the variant that the stream belongs to is
76
available in a metadata key named "variant_bitrate".
77

    
78
@c man end INPUT DEVICES