My main objective is to extract the I'th, I+1'th (next), I-1'th (previous) frames in the form of Y only (of YUV 420) from an mp4 video. The procedure which I am using right now is
I extracted the list of all the I frames from a video using the command - ffprobe "input.mp4" -show_frames | grep 'pict_type=I' -A 1 > frame_info.txt
Next, I used a python script to parse through this txt file to find the numbers of all of the I frames and then extracting all of the frames using the command - ffmpeg -i input.mp4 -vf select='eq(n\,{1}),setpts=N/25/TB,extractplanes=y' -vsync 0 -pix_fmt gray {1}.yuv This is happening via a subprocess call from python.
This is working fine for small resolution videos like 240p or 480p but as soon as I move to 1080p videos the time to extract even a single frame increases exponentially. As the ffmpeg seeks to that frame number to extract it and it has to decode the mp4 file till that point.
I have a lot of 1080p files and I was looking to decrease the time. The solution which I was thinking was to extract all of the Y frames (of YUV 420) from mp4 and then selecting only I frames as I've got the list of all of the I frames from step 1.. The command I am using for this is - ffmpeg -y -i input.mp4 -vf "fps=59.94" -pix_fmt gray file_name.yuv
The problem with the above code is that it continuously appends the to yuv file only but I want an individual y file for one frame of the mp4 video.
My restriction is to use FFmpeg only as FFmpeg's Y value is matching with what I want.
TL:DR - I want to extract the Y part only (of YUV 420p) from an mp4 video. The y frames are the I'th and I-1th and I+1th frames.
Thanks for helping out.
In step 1, instead of storing the frame numbers, store the pts_time.
Then, in step 2, run
ffmpeg -copyts -ss X -i input.mp4 -vf select='eq(t\,X),extractplanes=y' -vsync 0 -pix_fmt gray -vframes 1 {1}.yuv
where X is the pts_time.
Related
I am processing my video(640 X 1280 dimensions). I want to divide my video horizontally into 2 separate videos(each video will now be 640 X 640 in dimensions),then combine them horizontally (video dimension will be now 1280 X 640)in a single video. I did the research on the internet and my issue was solved and not solved at the same time
I made a batch file and add these commands in it:-
ffmpeg -i input.mp4 -filter_complex "[0]crop=iw:ih/2:0:0[top];[0]crop=iw:ih/2:0:oh[bottom]" -map "[top]" top.mp4 -map "[bottom]" bottom.mp4
ffmpeg -i top.mp4 -i bottom.mp4 -filter_complex hstack output.mp4
Yes,my task got solved but many other issues also came out of it:-
1.) My output video has NO audio in it. No idea why there is no audio in the end results
2.) My main video file (on which I am doing all this) is 258 MB in size. But the result was only 38 MB in size. No idea what is happening? And even worse,I closely looked at the video,results were pretty same (only animation were not as smooth in output file as compared to input file)
3.) It is taking too much time(I know that computing takes some time but maybe there may be some way/sacrifice to make the process much quicker)
Thanks in advance for helping me
Combine your two commands
ffmpeg -i input.mp4 -filter_complex "[0]crop=iw:ih/2:0:0[top];[0]crop=iw:ih/2:0:oh[bottom];[top][bottom]hstack" -preset fast -c:a copy output.mp4
If you need it to encode faster then use a faster -preset as shown in FFmpeg Wiki: H.264.
x264 is a better encoder than your phone so it is not surprising that the file size is smaller.
Or use your player to do it
No need to wait for encoding. Just have your player do everything upon playback. This does not output a file, but only plays the re-arranged video. Example using mpv:
mpv --lavfi-complex="[vid1]split[v0][v1];[v0]crop=iw:ih/2:0:0[c0];[v1]crop=iw:ih/2:0:oh[c1];[c0][c1]hstack[vo]" input.mp4
I have:
Video file of X length
Audio of Y length
I am trying to achieve an output video that has the following qualities:
The volume level of the added audio should be adjustable
The audio should loop till the end of the video
It should not break even if the input video does not have any audio
I should be able to mute the audio of the source video if needed.
All of the above, in the fastest possible way.
I'm not well versed with FFMPEG, maybe some experts could help.
since you are using a library i assume that you know how to run pure FFmpeg commands
based on your third condition we will divide the solution to two part :
It should not break even if the input video does not have any audio
in order to cover this condition, you can check if there is any audio stream in your video file before running any FFmpeg command with below code:
private boolean isVideoContainAudioStream(String videoPath) {
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
retriever.setDataSource(videoPath);
String hasAudioStream = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_HAS_AUDIO);
if (hasAudioStream != null && hasAudioStream.equals("yes"))
return true;
else
return false;
}
1. Part One :
so if the result of above function is equal to true, your video file contain audio stream so you can run below command :
ffmpeg -i video.mp4 -filter_complex "amovie=/path/to/audio/file/audio.mp3:loop=0,asetpts=N/SR/TB,volume=2.0[audio];[0:a]volume=0.5[sa];[sa][audio]amix[fa]" -map 0:v -map [fa] -vcodec libx264 -preset ultrafast -shortest fout.mp4
in above command we take audio file at a specific path with amovie filter
loop=0, Loop audio infinitely
asetpts=N/SR/TB, Generate timestamps by counting samples
volume=2.0, multiply audio volume by 2.0
video's audio stream is accessible with [0:a] filter pad so we take it and set the volume to half of the input's volume and name it [sa] obviously if you want to mute the audio of the source video you change that part to :
[0:a]volume=0.0[sa]
after that we will mix two audio streams using amix filter and name it [fa], so far we have everything we wanted, and we just want to merge audio and video streams
-vcodec libx264, we are using x264 video encoding because it has lots of configs to gain better performance and speed
-shortest, since we loop audio infinitely, we tell the ffmpeg to continue creating frames until the shortest stream ends (video stream is the short one for sure)
-preset ultrafast, preset is one of the x264 options, ultrafast will give you more encoding speed at the cost of more size in output file, usually using veryfast value for this flag is a good combination of speed and size
2. Part Two :
if the isVideoContainAudioStream function return false (which means your input video is muted) you can run below command:
ffmpeg -i mute_video.mp4 -filter_complex "amovie=/path/to/audio/file/audio.mp3:loop=0,asetpts=N/SR/TB,volume=2.0[audio]" -map 0:v -map [audio] -vcodec libx264 -preset ultrafast -crf 18 -shortest m_fout.mp4
in above command we use another x264 options called CRF
Constant Rate Factor (CRF)
Use this rate control mode if you want to keep the best quality and care less about the file size. This is the recommended rate control mode for most uses.
The range of the CRF scale is 0–51, where 0 is lossless, 23 is the default, and 51 is worst quality possible. A lower value generally leads to higher quality, and a subjectively sane range is 17–28. Consider 17 or 18 to be visually lossless or nearly so; it should look the same or nearly the same as the input but it isn't technically lossless.
The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size, while -6 leads to roughly twice the bitrate.
Choose the highest CRF value that still provides an acceptable quality. If the output looks good, then try a higher value. If it looks bad, choose a lower value.
thats it, there is lots of option for x264 encoder, you can check all available options at this link:
H.264 Video Encoding Guide
How can I change the Tone frequency.
This Example only pitches it by keeping the old tone frequency and only decrease the length of File.
For Example, I have a constant 100 Herz tone (as mp3) and I want it to change 90 Herz
ffmpeg -i 100h.mp3 -af atempo=100/90 90h.mp3
This Example doesn't work for me, it sounds the same
inputfile Mp3
outputfile Mp3
finally, by combining the asetrate and resample from Gyan, with atempo, the following works and preserves also the audio length
for example: use 0.9 for 90% of the frequenz
ffmpeg -i test.mp3 -af asetrate=44100*0.9,aresample=44100,atempo=1/0.9 output.mp3
Basic method is
ffmpeg -i 100h.mp3 -af asetrate=44100*0.9,aresample=44100 90h.mp3
where 44100 should be replaced with the input sample rate.
I have two videos of different lengths Video one: 12 minutes Video two: 6 minutes I want to take audio of video one I want to take image of video two And put them together Output video length = 6 minutes. Use ffmpeg one command please help me - thanks ( watch image )____
Use
ffmpeg -i 12m.mp4 -i 6m.mp4 -vf setpts=(PTS-STARTPTS)/1.1 -af atempo=1.1 -map 1:v -map 0:a -shortest new.mp4
The setpts filter alters the video frame timestamps to 1/1.1 of their present value. FFmpeg will drop frames in the cadence needed to preserve source framerate.
The atempo filter speeds up the audio to 1.1 times the original speed.
-map 1:v -map 0:a tells ffmpeg to include the video stream from the 2nd input (6m.mp4) and the audio from the first input.
-shortest tells ffmpeg to conclude conversion when the shorter (of the audio and video) stream ends.
how do I convert an animated gif to a video (e.g. h264#mp4) programmatically on a linux server?
I need this to process user generated content which should be output as several defined video formats; therefore its possible, that users may want to process animated gif files. I already have a set of working php scripts to transcode videofiles to specific formats (like vpx#webm and h264#mp4, scaled to specific resolutions) using avconv, but herefore I need video input.
Usual ways seem to be to extract the frames of the gif and then encode it, like
convert file.gif file%03d.png
avconv -i file%03d.png file.mp4
But this discards the frame rate, determined by the pause-informations within the gif-file. Its possible to define a framerate to avconv with -r, but
this does not respect the pause between frames, as they can differ (like 1st frame 100ms pause, 2nd frame 250ms pause, 3rd frame 100ms pause, ...)
as the input comes from users, it may even vary, as some gifs may have 5fps and others 30fps
I noticed that avconv is able to process gifs by itself and therefore may respect the correct pauses, but when I do (like similarily described in How to convert GIF to Mp4 is it possible?)
avconv -i file.gif -r 30 file.mp4
avconv will only take the first frame of the gif, while it detects the file at least as video:
Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
Stream #0.0: Video: gif, pal8, 640x480, 25 tbn
(example gif 'file.gif' has 15 frames, each with 100ms pause => 1.5s duration, looping)
What am I missing? Whats going wrong?
Are there probably better tools for this use case?
What are big sites like e.g. 9gag using to transcode uploaded gifs to video?
Yet Another Avconv Bug (YAAB)
ffmpeg has better GIF demuxing support (and improved GIF encoding). I recommend ditching avconv and getting ffmpeg (the real one from FFmpeg; not the old charlatan from Libav). A static build is easy, or you can of course compile.
Example
ffmpeg -i in.gif -c:v libx264 -pix_fmt yuv420p -movflags +faststart out.mp4
See the FFmpeg Wiki: H.264 Encoding Guide for more examples.
If for some reason you are required to use avconv and imagemagick, you may want to try something like this:
ticks_per_frame = subprocess.check_output('identify -verbose -format %T_ {0}'.format(gif_path).split()).split('_')[:-1]
ticks_per_frame = [int(i) for i in ticks_per_frame]
num_frames = len(ticks_per_frame)
min_ticks = min(ticks_per_frame)
subprocess.call('convert -coalesce {0} tmp%d.png'.format(gif_path).split())
if len(set(ticks_per_frame)) > 1:
num_dup = 0
num_dup_total = 0
for frame, ticks in enumerate(ticks_per_frame):
num_dup_total += num_dup
frame += num_dup_total
num_dup = 0
if ticks > min_ticks:
num_dup = (ticks / min_ticks) - 1
for i in range(num_frames + num_dup_total - 1, frame, -1):
orig = 'tmp%d.png' % i
new = 'tmp%d.png' % (i + num_dup)
subprocess.call(['mv', orig, new])
for i in range(1, num_dup + 1):
curr = 'tmp%d.png' % frame
dup = 'tmp%d.png' % (i + frame)
subprocess.call(['cp', curr, dup])
framerate = (100 / min_ticks) if min_ticks else 10
subprocess.call('avconv -r {0} -i tmp%d.png -c:v libx264 -crf {1} -pix_fmt yuv420p \
-vf scale=trunc(iw/2)*2:trunc(ih/2)*2 -y {2}.mp4'.format(framerate, quality, STORAGE_DIR + mp4_name).split())
subprocess.call(['rm'] + glob('tmp*.png'))
So, get the ticks in centiseconds for each frame of the gif (via identify), convert to multiple pngs, and then go through them while making duplicates based on the tick values. And don't you worry, the png files will still remain in consecutive order. Using the real FFmpeg is still the best way to go.