If I use:
melt -profile square_ntsc movie.flv -consumer avformat:image%05d.jpg s=60x45
I get so many images as many frames are in movie.
How do I extract an image each second? (the frame rate is known). Same as how do I extract an image every n-th frame.
found the answer: just add a r=1 for consumer, like in:
melt -profile square_pal movie.flv -consumer avformat:image%05d.jpg r=1
to get 2 images each second, write:
melt -profile square_pal movie.flv -consumer avformat:image%05d.jpg r=2
to get images each 2 seconds, write:
melt -profile square_pal movie.flv -consumer avformat:image%05d.jpg r=0.5
Related
Consider the following bash script (on Ubuntu 18.04, melt 6.6.0), which uses melt to make a slideshow and play it locally in a window (SDL consumer), mostly copied from https://mltframework.org/blog/making_nice_slideshows/ ( edit: I'm aware that's its possible to specify files individually as in https://superuser.com/questions/833232/create-video-with-5-images-with-fadein-out-effect-in-ffmpeg/834035#834035 - but that approach seems to scale images during transition, and takes quite a while to "render" before playing in SDL window, while this one has nearly instant playback):
echo "
description=DV PAL
frame_rate_num=25
frame_rate_den=1
width=720
height=576
progressive=0
sample_aspect_num=59
sample_aspect_den=54
display_aspect_num=4
display_aspect_den=3
colorspace=601
" > my-melt.profile
mkdir tmppics
convert -background lightblue -fill blue -size 3840x2160 -pointsize 200 -gravity center label:"Test A" tmppics/pic_01.jpg
convert -background lightblue -fill blue -size 3840x2160 -pointsize 200 -gravity center label:"Test B" tmppics/pic_02.jpg
melt -verbose -profile ./my-melt.profile \
./tmppics/.all.jpg ttl=6 \
-attach crop center=1 \
-filter luma cycle=6 duration=4 \
-consumer sdl
When I run the above command, the video shows the two images loop, but the frame counter keeps on going, increasing indefinitely. How do I make it stop after the exact amount of frames that the loop is long?
As far as I can see, the size of the output video is controlled by a profile; that is, even if I don't specify -profile, a default one is assumed; is that correct?
The original images look like this:
... and the video looks like this:
... which means the aspect ratio is wrong; additionally I can see jagged edges, meaning the scaled image in the video is not antialiased.
How do I make the image fit in video size with correct aspect ratio, with antialiasing/smoothing? (I guess it has to do with -attach crop center=1, but I couldn't find documentation on that).
When viewing stuff in SDL and stepping through frames, are frames numbered 0-based, - or are they 1-based, and at frame 0 simply the same frame as 1 is shown?
If I use ttl=6 and -filter luma cycle=6 duration=4, I get this:
... that is, visible transition starts at frame 7 (frame 6 is full image A), lasts for frames 7 and 8, and ends at frame 9 (which is full image B); then again at frames 13 and 14 (frame 15 is full image A)
However, if I use ttl=6 and -filter luma cycle=6 duration=2, then I get this:
... that is, there is no transition, image instantly changes at frame 7, then again at frame 13, etc.
So, I'd call the first case a transition duration of 2 frames, and the second case a duration of 0 frames - yet the options are duration=4 and duration=2, respectively. Can anyone explain why? Where are those 2 frames of difference gone?
Can I - and if so, how - do the same kind of slideshow, except with fade to black? I'd like to define a "time to live" (ttl) of 6 frames per image, and a transition of 4 frames, such that:
first, 4 frames are shown of image A;
then one frame image A faded, followed by one frame black (amounting to 6 frames TTL for image A, the last 2 transition);
then two frames image B faded (amounting to 4 frames transition with previous 2), followed by two more frames image B full (so 4 frames here of image B);
then one frame image B faded, followed by one frame black (amounting to 6 frames TTL for image B);
... etc.
Is it possible to persuade melt to use globbing to select images for slideshow, instead of using .all.jpg? As far as I can see on MLT (Media Lovin' Toolkit) Photo Slide Video no - but maybe there is another approach...
Ok, so, I spent some time looking into the commands for melt and turns out there is actually a pretty effective way of altering a bunch of images (if the number of arguments is too long or there are too many characters for your terminal to handle).
What you want to do is to use -serialise <name of file>.melt which will store your commands (you can also create this file manually). Then to execute that file, use melt <name of file>.melt along with any other options you have for your video file.
Example Format:
melt <images and what to do to them> -serialise <name of file>.melt
Example
Create the melt file (with Melt CLI)
melt image1.png out=50 image2.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image4.png out=75 -mix 25 -mixer luma <...> -serialise test.melt
.melt file format
test.melt
image1.png
out=50
image2.png
out=75
-mix
25
-mixer
luma
image3.png
out=75
-mix
25
-mixer
luma
image3.png
out=75
-mix
25
-mixer
luma
image4.png
out=75
-mix
25
-mixer
luma
<...>
Run
melt test.melt -profile atsc_1080p_60 -consumer avformat:output.mp4 vcodec=libx264 an=1
Additional Notes
There should be an extra return character at the end of the melt file. If there isn't, Exceeded maximum line length (2048) while reading a melt file. will be outputted
Notice that -serialise <name of file>.melt will not be in the .melt file
Melt will actually take some time to load the melt file before the encoding process begins
I'm seeking to mix 2 clips, however, I'd like for clip2 to start after the mixer transition ends, not begins.
Essentially, this should mix clip1 with only clip2's frame 0.
I was wondering if there was a better alternative to my current workaround:
melt \
clip1.mp4 \
clip2.mp4 in=0 out=0 length=300 \
-mix 300 -mixer luma \
clip2.mp4
Perhaps there is something to pause clip2 at frame 0 for 300 frames?
(I'm doing this with 2 .mlt clips, but voiding the audio_index doesn't seem to work on mlt clips, thus I get a small audio jump for 1 frame, so this workaround isn't ideal)
You cannot set audio_index on .mlt virtual clips because audio_index is a property of the avformat producer, but MLT XML is read by the xml producer.
You can use the hold producer to hold a frame and mute audio. It defaults to 25 frames duration; so use out to override it:
melt clip1.mp4 hold:clip2.mp4 frame=0 out=299 -mix 300 -mixer luma clip2.mp4
I am using the Tesseract library to extract text from images. The language is Vietnamese. I have two images. The first one is from a website. The second is a screenshot taken from the Wordpad program. They are shown in links below:
1
2
The first one has 95% accuracy.
Bán căn hộ tầng 5 khu tập thể Thành công Bắc, DT 28m2, gần chợ ThànhCông,
số
đỏ, chính chủ, giá 800 triệu.LH:A.Châu, 0979622551,0905685336
The second image is much larger but the accuracy is just about 60%.
Bặn căn hộ tầng ậ khu tập thể Ỉhành gông
Băc. llĩ 28 m2. gân chợ ĩllành Bông. sũ Ilỏ.
chính l:lIlì. giá 800 lriệu. l.ll: A.BhâU,
0979622551, 0905685336
What about the second image do I have to fix to get as accurate text as the first one?
As stated by #user898678 in image processing to improve tesseract OCR accuracy ,
the following operations can improve OCR's accuracy :
fix DPI (if needed) 300 DPI is minimum
fix text size (e.g. 12 pt should be ok)
try to fix text lines (deskew and dewarp text)
try to fix illumination of image (e.g. no dark part of image
binarize and de-noise image
The code for my question is as follows:
def score_Calc(par, strokes, hole_number):
if strokes == par - 1:
print ('On hole #',hole_number, 'a par',par,'you shot a birdie.')
def score_Calcs (par, strokes, hole_number):
if strokes == 1:
print('with a Hole in One!')
My question is this: How can I get the printed results on one line? Right now, I've got it printing out as:
On hole # 5 a par 5 you shot 5 over par.
with a Bo Derek. Bummer.
How can I get it to print out as this?
On hole # 5 a par 5 you shot 5 over par. with a Bo Derek. Bummer.
I realize the code doesn't make much sense, as it is not my full program. My problem is when I execute the main function, it prints out as two seperate lines. How can I make it just one line with the input from the two different functions?
By default, print ends with a newline character. This call
print("Hello World")
is in reality used like that by Python :
print("Hello World", end='\n')
Basically you just need to change the ending :
print ('On hole #',hole_number, 'a par',par,'you shot a birdie.', end=' ')
I have a pygame.Timer running in my game calling a draw function 32 times/second. The drawing method gets positions from all elements on my screen and blits them accordingly. However, I want the main character to walk around slower than other objects move.
Should I set up a timer specifically for it or should I just blit the same frames several times? Is there any better way to do it? A push in the right direction would be awesome :)
(If anyone's interested, here is the code that currently controls what frames to send to the drawing: http://github.com/kallepersson/subterranean-ng/blob/master/Player.py#L88)
Your walk cycle frame (like all motion) should be a function of absolute time, not of frame count. e.g.:
def walk_frame(millis, frames_per_second, framecount, start_millis=0):
millis_per_frame = 1000 / frames_per_second
elapsed_millis = millis - start_millis
total_frames = elapsed_millis / millis_per_frame
return total_frames % framecount