Newest 'ffmpeg' Questions - Stack Overflow

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Les articles publiés sur le site

  • How to read the Y, U, V of each pixel from the YUV format image [on hold]

    28 mai 2017, par xinyue Liu

    I'm currently have a YUV image. Do you have any suggestion on how to extract y,u,v components of each pixel from the image?

  • How can I change a video frame rate with FFmpeg keeping the same total number of frames ?

    28 mai 2017, par Nuno

    I've been searching for an answer here on Stack Overflow and googling everywhere... even though it seems like it should be a very simple command line to me, I just can't find an answer anywhere.

    I would like to change the frame rate of a video from 23.976fps to 24fps with FFmpeg, lossless and keeping the total number of frames.

    To make it simpler:

    Let's say I have a 25fps video with a total lenght of 100 frames.

    How can I change it's frame rate to 50fps, with FFmpeg, lossless and keeping the same total lenght of 100 frames?

    This was so far the best solution I came across with (which can be found here):

    Extract the frames as rawvideo:

    ffmpeg -i input.mov -f rawvideo -b 50000000 -pix_fmt yuv420p -vcodec rawvideo -s 1920x1080 -y temp.raw

    Recreate the video with new framerate:

    ffmpeg -f rawvideo -b 50000000 -pix_fmt yuv420p -r 24 -s 1920x1080 -i temp.raw -y output.mov

    Note 1: I had to remove "-b 50000000" when recreating the video with the new frame rate, in order to get it to work properly.

    It did exactly what I intended it to do, but I'm still wondering if there is any simpler way to do this? I've tried to pipe them together in one line only, as suggested in the same post, but couldn't get it to work.

    Note 2: Even though it does exactly what I wanted it to do, I've just later realized there is quality loss using this method, which I would prefer to avoid.

    Thanks everyone in advance!

  • How to upload a video through PHP, transcode it via FFmpeg and upload it to a different server via FTP

    28 mai 2017, par PBXAI

    Currently I am building a video streaming platform and I need a way to upload my videos, through multiple resolutions to my Wowza server. I am currently running Ubuntu with Nginx, PHP and Wowza so I want to be able to, when the user uploads the video, encode it to 1080p, 720p, 480p, and 360p. How would I do this?

  • reduce bitrate using ffmpeg

    27 mai 2017, par WantIt

    I have this command to run with ffmpeg to reduce bitrate.

    ffmpeg -y -i input.mp4 -b:v 1024k output_1024k.mp4

    where we want to take the input file and just reduced it's bitrate (just 1024k). It works in the commandline. Now, I like to reduce bitrate via Java. I decided to use bytedeco/javacv FFmpegFrameGrabber and FFmpegFrameRecorder to perform the same function. Below is my code:

    FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("input.mp4");
            grabber.start();

            FrameRecorder recorder = new FFmpegFrameRecorder("out.mp4", grabber.getAudioChannels());
            recorder.setSampleRate(256);
            recorder.start();

            Frame frame;
            while ((frame = grabber.grabFrame()) != null) {
                recorder.record(frame);
            }
            recorder.stop();
            grabber.stop();

    but it is saying the following error:

    org.bytedeco.javacv.FrameRecorder$Exception: avcodec_open2() error -22: Could not open audio codec.
    at org.bytedeco.javacv.FFmpegFrameRecorder.startUnsafe(FFmpegFrameRecorder.java:732)
    at org.bytedeco.javacv.FFmpegFrameRecorder.start(FFmpegFrameRecorder.java:351)
    at com.goxhere.api.monte.resources.VideoResource.uploadFile(VideoResource.java:337)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:74)
    at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144)
    at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161)
    at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:247)
    at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:388)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:346)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)
    at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:337)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:280)
    at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:316)
    at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1084)
    at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:418)
    at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:372)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:389)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:342)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:229)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

    Basically the error says I have problem with audio codec, but when I tried to run the ffmpeg commandline directly, it reduces the bitrate just fine. Are we missing some setup in javacode? Thank you.

  • PHP large video upload converting to mp3 by ffmpeg

    27 mai 2017, par SuperBerry

    I am working on a project on Linux VPS (Apache + PHP5, 4G RAM / 2 CPU Cores) which allows users to upload videos (200M max) and convert to MP3 audio files by FFMPEG. I have few questions about the concurrency and the processing because I am a newbie on PHP:

    1. If there are 10 visitors uploading (1 visitor uploads one 200M MP4 file), will it cost 2,000M memory of the server? Will the chunk upload method could solve this memeory issue while more visitors uploading videos at the same time?

    2. I am going to use Redis to manage the ffmpeg processing queue, and set the crontab. Should I use the shell_exec() to call the ffmpeg to process the conversion at background, then convert the uploaded videos one by one?

    The uploading and conversion is the most cost for the server I think... Maybe my idea is extremely crazy...I am new to this type of service.. I didn't make online projects before, just desktop apps...

    Thanks a lot for your help..

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