Newest 'ffmpeg' Questions - Stack Overflow

http://stackoverflow.com/questions/tagged/ffmpeg

Les articles publiés sur le site

  • how do I convert .iso to .mp4 without mounting with ffmpeg [migrated]

    29 août 2011, par teferi

    The problem is - I want to convert .iso with dvd to .mp4 (h264/ac3), but I cannot mount it via mount -o loop, because I'm on a virtual machine that doesn't allow to do that.

    Googling doesn't help.

    For now I'm trying to use mencoder for the task, but it's hard for me to convert all the parameters from ffmpeg-style to mencoder style.

  • converting .mov file to .h264 file

    29 août 2011, par Robin Rye

    ok, this is the case, i actually want to parse frames from a mov file. get the encoded h264 frames. and i've managed to do so by using ffmpeg but when i try to make a movie again by using ffmpeg -i test* test.mov i get test00: Invalid data found when processing input so there is something not correct with the structure of the frames. as i understand it a frame should have the following appearance:

    00 00 00 01 XX data -------------

    where XX is say whether it is a I-,P- or B-frame. or more specifically type(XX) = 0x0F && XX says if it is I(type(XX) = 5?),P(type(XX) = 7?) or B(type(XX) = 8?) frame. I'm not sure about these number, i've been looking for it but not found good sources. so that's question number one, what number should the NALU be for the different frames?

    anyway, when i use av_read_frame on the mov file, i get frame that look like this:

    4B = size, 1B = XX and then data. (at least this is what i think i get)

    the files where i store the frames are always size long when i look at them in a hexeditor(otherwise as well of course). and XX is always 65(ie. type(XX) = 5) in the first and then 61(ie. type(XX) = 1) for a couple of frames and then back to being 65 for one frame and so on.

    i guess that these are frames like: I P P P P P P I P P P P P P P I P P P P P P P .... however then my assumption about the type numbers for the different frame types are false, which is highly likely. (any suggestion on reading about this? except the ISO/IEC 14496-10, i don't understand it really).

    I've tried to remove the size and append 00 00 00 01 before the XX byte and the data but without success. any tips on how i could modify the frames to be valid H264 encoded frames?

  • PHP FFmpeg video aspect ratio problem [SOLVED]

    29 août 2011, par Herr Kaleun

    i compiled the new version of FFMPEG and the padding commands have been deprecated.
    As i try to get familiar with the new -vf pad= commands, i want to ask, how can i
    convert a video without changing it's aspect ratio.

    I've checked numerous solutions from stackoverflow, nothing seemed to work.
    Can someone, please post a working PHP example or cmd line. I would be VERY happy.

    Please note that the videos in question, could be 4:3 and also be 16:9

    Let's say, i convert a 16:9 video to 640x480 format. It will need some bars at
    the top and at the bottom. That is what i want to do.

    Thanks

    EDIT:
    I solved the problem on my own. The FFmpeg documentation is a little bit weird so
    you have to experiment yourself a little bit.
    The padding formula is like: 

        $pad_horizontal = $target_width     + $pad_left + $pad_right;
    $pad_vertical   = $target_height;
    // blah
    $command .= " -vf pad=$pad_horizontal:$pad_vertical:". $pad_left .":". $pad_top  .":black";

    Pay special attention at the $pad_vertical part since the paddings there are better
    not added so that the padding calculation of ffmpeg is not broken.

    Here is the full source code to the demo 

    <?

    /***********************************************************************************
    get_dimensions()

    Takes in a set of video dimensions - original and target - and returns the optimal conversion
    dimensions.  It will always return the smaller of the original or target dimensions.
    For example: original dimensions of 320x240 and target dimensions of 640x480.
    The result will be 320x240 because converting to 640x480 would be a waste of disk
    space, processing, and bandwidth (assuming these videos are to be downloaded).

    @param $original_width:     The actual width of the original video file which is to be converted.
    @param $original_height:    The actual height of the original video file which is to be converted.
    @param $target_width:       The width of the video file which we will be converting to.
    @param $target_height:      The height of the video file which we will be converting to.
    @param $force_aspect:       Boolean value of whether or not to force conversion to the target's
                          aspect ratio using padding (so the video isn't stretched).  If false, the
                          conversion dimensions will retain the aspect ratio of the original.
                          Optional parameter.  Defaults to true.
    @return: An array containing the size and padding information to be used for conversion.
                Format:
                Array
                (
                    [width] => int
                    [height] => int
                    [padtop] => int // top padding (if applicable)
                    [padbottom] => int // bottom padding (if applicable)
                    [padleft] => int // left padding (if applicable)
                    [padright] => int // right padding (if applicable)
                )
    ***********************************************************************************/
    function get_dimensions($original_width,$original_height,$target_width,$target_height,$force_aspect)
    {
        if(!isset($force_aspect))
        {
            $force_aspect = true;
        }
        // Array to be returned by this function
        $target = array();
        $target['padleft'] = 0;
        $target['padright'] = 0;
        $target['padbottom'] = 0;
        $target['padtop'] = 0;



        // Target aspect ratio (width / height)
        $aspect = $target_width / $target_height;
        // Target reciprocal aspect ratio (height / width)
        $raspect = $target_height / $target_width;

        if($original_width/$original_height !== $aspect)
        {
            // Aspect ratio is different
            if($original_width/$original_height > $aspect)
            {
                // Width is the greater of the two dimensions relative to the target dimensions
                if($original_width < $target_width)
                {
                    // Original video is smaller.  Scale down dimensions for conversion
                    $target_width = $original_width;
                    $target_height = round($raspect * $target_width);
                }
                // Calculate height from width
                $original_height = round($original_height / $original_width * $target_width);
                $original_width = $target_width;
                if($force_aspect)
                {
                    // Pad top and bottom
                    $dif = round(($target_height - $original_height) / 2);
                    $target['padtop'] = $dif;
                    $target['padbottom'] = $dif;
                }
            }
            else
            {
                // Height is the greater of the two dimensions relative to the target dimensions
                if($original_height < $target_height)
                {
                    // Original video is smaller.  Scale down dimensions for conversion
                    $target_height = $original_height;
                    $target_width = round($aspect * $target_height);
                }
                //Calculate width from height
                $original_width = round($original_width / $original_height * $target_height);
                $original_height = $target_height;
                if($force_aspect)
                {
                    // Pad left and right
                    $dif = round(($target_width - $original_width) / 2);
                    $target['padleft'] = $dif;
                    $target['padright'] = $dif;
                }
            }
        }
        else
        {
            // The aspect ratio is the same
            if($original_width !== $target_width)
            {
                if($original_width < $target_width)
                {
                    // The original video is smaller.  Use its resolution for conversion
                    $target_width = $original_width;
                    $target_height = $original_height;
                }
                else
                {
                    // The original video is larger,  Use the target dimensions for conversion
                    $original_width = $target_width;
                    $original_height = $target_height;
                }
            }
        }
        if($force_aspect)
        {
            // Use the target_ vars because they contain dimensions relative to the target aspect ratio
            $target['width'] = $target_width;
            $target['height'] = $target_height;
        }
        else
        {
            // Use the original_ vars because they contain dimensions relative to the original's aspect ratio
            $target['width'] = $original_width;
            $target['height'] = $original_height;
        }
        return $target;
    }

    function get_vid_dim($file)
    {
        $command = '/usr/bin/ffmpeg -i ' . escapeshellarg($file) . ' 2>&1';
        $dimensions = array();
        exec($command,$output,$status);
        if (!preg_match('/Stream #(?:[0-9\.]+)(?:.*)\: Video: (?P.*) (?P[0-9]*)x(?P[0-9]*)/',implode("\n",$output),$matches))
        {
            preg_match('/Could not find codec parameters \(Video: (?P.*) (?P[0-9]*)x(?P[0-9]*)\)/',implode("\n",$output),$matches);
        }
        if(!empty($matches['width']) && !empty($matches['height']))
        {
            $dimensions['width'] = $matches['width'];
            $dimensions['height'] = $matches['height'];
        }
        return $dimensions;
    }


    $command    = '/usr/bin/ffmpeg -i ' . $src . ' -ab 96k -b 700k -ar 44100 -f flv -s ' . '640x480 -acodec mp3 '. $video_output_dir . $video_filename . ' 2>&1';


    define( 'VIDEO_WIDTH',      '640' );
    define( 'VIDEO_HEIGHT',     '480' );

    $src_1              = getcwd() .'/'. 'test_video1.mpeg';
    $video_filename1    = 'video1.flv';

    $src_2              = getcwd() .'/'. 'test_video2.mp4';
    $video_filename2    = 'video2.flv';

    $src_3              = getcwd() .'/'. 'test_video3.mp4';
    $video_filename3    = 'video3.flv';

    convert_video( $src_1, $video_filename1 );
    convert_video( $src_2, $video_filename2 );
    convert_video( $src_3, $video_filename3 );

    function convert_video( $src = '', $video_filename = '' )
    {

        $video_output_dir   = getcwd() .'/';

        @unlink ( $video_output_dir . $video_filename );

        $original   = get_vid_dim($src);
        $target     = get_dimensions( $original['width'], $original['height'], VIDEO_WIDTH, VIDEO_HEIGHT, TRUE );

        echo '
    ';
        print_r( $original );
        echo '
    ';
        echo '
    ';
        print_r( $target );
        echo '
    ';



        $target_width   = $target['width'];
        $target_height  = $target['height'];

        $pad_left       = $target['padleft'];
        $pad_right      = $target['padright'];
        $pad_bottom     = $target['padbottom'];
        $pad_top        = $target['padtop'];

        $pad_horizontal = $target_width     + $pad_left + $pad_right;
        $pad_vertical   = $target_height; //    + $pad_top + $pad_bottom;


        $command = '/usr/bin/ffmpeg -i ' . $src;

        // $command .= " -s {$target_width}x{$target_height} ";

        $command .= " -vf pad=$pad_horizontal:$pad_vertical:". $pad_left .":". $pad_top  .":black";

        $command .= ' -ab 96k -b 700k -ar 44100';
        $command .= ' -f flv ';
        $command .= ' -qscale 4';

        $command .= ' -ss 30';
        $command .= ' -t 5';

        $command .= ' -ac 2 -ab 128k -qscale 5 ';
        $command .= ' ' . $video_output_dir . $video_filename;


        exec( $command, $output, $status );

        echo '
    ';
        print_r( $command );
        echo '
    ';

        if ( $status == 0 ) 
        {
            echo '
    Convert OK. 
    ';
        }
        else
        {
            echo '
    ';
            print_r( $output );
            echo '
    ';
        }

        echo '
    ';
        echo '
    ';

    }





?>

    Thank you and have fun :)

  • Decode h264 video with csharp

    28 août 2011, par john bowring

    I am looking for a way to decode h264 (or indeed any video format) using c#. The ultimate goal is to be able to decode the images and very strictly control the playback in real time. The project I am working on is a non-linear video art piece where the HD footage is required to loop and edit itself on the fly, playing back certain frame ranges and then jumping to the next randomly selected frame range seamlessly.

    I have created an app which reads image files (jpegs) in from the disk and plays them on screen in order, I have total control over which frame is laoded and when it is displayed but at full HD res it takes slightly longer than I want to load the images from hard drive (which are about 500k each), I am thinking that using a compressed video format would be smaller and therefore faster to read and decode into a particular frame however I cannot find any readily avaiable way to do this.

    Are there any libraries which can do this? i.e. extract an arbitrary frame from a video file and serve it to my app in less time than it takes to show the frame (running at 25fps), I have looked into the vlc libraries and wrappers for ffmpeg but I don't know which would be better or if there would be another even better option. Also I dont know which codec would be the best choice as some are keyframe based making arbitrary frame extraction probably very difficult.

    Any advice welcome, thanks

  • How do I convert a sequence of images into a movie that the filename does not start from 1 ?

    27 août 2011, par Vique

    I have a sequence of images to be converted into a movie. The only problem is that, I wanted to start converting image number 120 until 240 into a movie using ffmpeg but I don't know the command line for that. Is there any possible command line for this kind of case?

Navigation

Sites Web