I was wondering if there is a preferred way to print a nice visual representation of a Graph, like the one seen here:
+------+
In1 ~>| |~> Out1
| bidi |
Out2 <~| |<~ In2
+------+
Related
I tried to concatenate a number of video files:
$ melt file01.mp4 file02.mp4 filen.mp4 170_ot_proof.mp4 170_thanks.mp4 -consumer "avformat:total.mp4" acodec=libmp3lame vcodec=libx264
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
|1=-10| |2= -5| |3= -2| |4= -1| |5= 0| |6= 1| |7= 2| |8= 5| |9= 10|
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
+---------------------------------------------------------------------+
| H = back 1 minute, L = forward 1 minute |
| h = previous frame, l = next frame |
| g = start of clip, j = next clip, k = previous clip |
| 0 = restart, q = quit, space = play |
+---------------------------------------------------------------------+
[mp4 # 0x7fc5b4001180] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
[mp4 # 0x7fc5b4001180] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
[mp4 # 0x7fc5b4001180] Timestamps are unset in a packet for stream 1. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
[mp4 # 0x7fc5b4001180] Encoder did not produce proper pts, making some up.
Current Position: 4599
The problem is that the produced file is 1 frame too long:
$ function get_fps() {melt "$1" -consumer xml | grep length | sed 's/[^0-9]//g';}
$ get_fps "total.mp4"
4601
$ tot=0; for file in file01.mp4 file02.mp4 filen.mp4 170_ot_proof.mp4 170_thanks.mp4; do tot=$(($tot + $(get_fps "$file"))); done; echo $tot
4600
After inspecting with KDEnlive, it seems like the added frame is in the last clip, not sure if it's just the last frame that is duplicated or another one.
This always occurs for the same set of files, but if I remove some files the issue is not always here… I made sure to set all files at 24fps.
I really don't understand what's going wrong here. Any idea?
Edit
On the other hand, ffprobe gives:
$ ffprobe -select_streams v -show_streams ../total.mp4 | grep nb_frame
nb_frames=4600
and this also gives the same number (but takes much more time, like if it were decoding the video instead of reading the headers):
$ ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -print_format csv ../total.mp4
stream,4600
I also tried to use cv2.CAP_PROP_FRAME_COUNT that also gives me 4600, so I'm a bit lost… If KDEnlive/melt give a different number than ffprobe, who should I trust?
When seeing:
void my_object_release(struct kobject *kobj)
{
struct my_object *mine = container_of(kobj, struct my_object, kobj);
/* Perform any additional cleanup on this object, then... */
kfree (mine);
}
in LWN’s The zen of kobjects, it seems incorrect in the third parameter kobj. I think it should be kobject.
The given code is correct: the third argument is the name of the container structure member to which the pointer points, not its type, so kobj is right. The example is somewhat confusing since the first kobj doesn’t correspond to the same thing as the second kobj: the first is the pointer in the caller’s scope.
Here’s a diagram to hopefully clarify the parameters of container_of:
container_of(kobj, struct my_object, kobj)
| | |
| | |
\------------+----------+--------------------------------\
| | |
| | |
/-----------------/ | |
| | |
V /-------------/ |
+------------------+ | |
| struct my_object | { | |
+------------------+ V V
+------+ +------+
struct kobject | kobj |; <-- You have a pointer to this, called | kobj |
+------+ +------+
...
};
container_of allows you to pass around a kobject pointer and find the containing object (as long as you know what the containing object is) — it allows you to use your knowledge of “what” to answer “where”.
It’s worth pointing out that container_of is a macro, which is how it can do seemingly impossible things (for developers not used to meta-programming).
I have a 128-bit vector of 4 floats that have been calculated, and I want to change the order of this vector like so:
Vector A before reordering
+---+---+---+---+
| a | b | c | d |
+---+---+---+---+
Vector A after reordering
+---+---+---+---+
| b | a | c | d |
+---+---+---+---+
As I said the vector has been calculated by earlier computations so no way to use _mm_set_ps()... Anyone have a clue on how can it be done?
You're looking for the SHUFPS instruction (shuffle packed single-precision floats).
The corresponding intrinsic is _mm_shuffle_ps:
__m128 _mm_shuffle_ps(__m128 a, __m128 b, unsigned int imm8);
The third parameter, an 8-bit immediate, is the permutation. This indicates how you want the values to be shuffled. To create this readably, you'll want to use the _MM_SHUFFLE macro. Here's a helpful graphical description of how _MM_SHUFFLE works, taken from some old Microsoft documentation:
I'm learning batch for the fun of it (so I can make quick and simple games), and it would be great if I could print at certain coordinates. How do I do this? Can I do this? Something like gotoxy(x,y) in C++.
Example:
___________________
| |
| |
| Print here |
| |
| |
|___________________|
I need to loop over all (unordered) pairs of pixels in an image that are neighbors of each other without repetition. I am using an 8 point neighborhood. For example:
x,y| 0 1 2 3 4
---+---+---+---+---+---+
0 | | | | | |
+---+---+---+---+---+
1 | a | b | c | d | |
+---+---+---+---+---+
2 | e | f | g | h | |
+---+---+---+---+---+
3 | i | j | k | l | |
+---+---+---+---+---+
4 | | | | | |
+---+---+---+---+---+
The neighbors of pixel f are in the 3x3 square around it. Thus, g, for example, forms a 2 point clique with f. If I were to loop over all the rows and columns of the image, this clique would be counted twice, once when f is the center pixel and once when g is the center pixel. Similar inefficiencies would occur with the rest of the cliques.
So what I would like to do, is loop over all the cliques, rather than each pixel. If I were familiar with graph theory, I think some of the answers already given to similar questions would suffice, but as I am not, I would really appreciate any help that you can give with an efficient algorithm in layman's terms. Thanks in advance!
Loop the first point over all points. Inner loop the second point over the right, lower-left, lower, and lower-right neighbors (if they exist).