74 lines
2.4 KiB
Plaintext
74 lines
2.4 KiB
Plaintext
@TEMPLATE decoder_tmpl.c
|
|
Decode With Drops Example
|
|
=========================
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
|
|
This is an example utility which drops a series of frames, as specified
|
|
on the command line. This is useful for observing the error recovery
|
|
features of the codec.
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION
|
|
|
|
Usage
|
|
-----
|
|
This example adds a single argument to the `simple_decoder` example,
|
|
which specifies the range or pattern of frames to drop. The parameter is
|
|
parsed as follows:
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ USAGE
|
|
if(argc!=4)
|
|
die("Usage: %s <infile> <outfile> <N-M|N/M>\n", argv[0]);
|
|
{
|
|
char *nptr;
|
|
n = strtol(argv[3], &nptr, 0);
|
|
m = strtol(nptr+1, NULL, 0);
|
|
is_range = *nptr == '-';
|
|
if(!n || !m || (*nptr != '-' && *nptr != '/'))
|
|
die("Couldn't parse pattern %s\n", argv[3]);
|
|
}
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ USAGE
|
|
|
|
|
|
Dropping A Range Of Frames
|
|
--------------------------
|
|
To drop a range of frames, specify the starting frame and the ending
|
|
frame to drop, separated by a dash. The following command will drop
|
|
frames 5 through 10 (base 1).
|
|
|
|
$ ./decode_with_drops in.ivf out.i420 5-10
|
|
|
|
|
|
Dropping A Pattern Of Frames
|
|
----------------------------
|
|
To drop a pattern of frames, specify the number of frames to drop and
|
|
the number of frames after which to repeat the pattern, separated by
|
|
a forward-slash. The following command will drop 3 of 7 frames.
|
|
Specifically, it will decode 4 frames, then drop 3 frames, and then
|
|
repeat.
|
|
|
|
$ ./decode_with_drops in.ivf out.i420 3/7
|
|
|
|
|
|
Extra Variables
|
|
---------------
|
|
This example maintains the pattern passed on the command line in the
|
|
`n`, `m`, and `is_range` variables:
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_VARS
|
|
int n, m, is_range;
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_VARS
|
|
|
|
|
|
Making The Drop Decision
|
|
------------------------
|
|
The example decides whether to drop the frame based on the current
|
|
frame number, immediately before decoding the frame.
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE
|
|
if((is_range && frame_cnt >= n && frame_cnt <= m)
|
|
||(!is_range && m - (frame_cnt-1)%m <= n)) {
|
|
putc('X', stdout);
|
|
continue;
|
|
}
|
|
putc('.', stdout);
|
|
fflush(stdout);
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE
|