Recherche avancée

Sur d’autres sites (4565)

• parsing different ffmpeg -i output

  11 août 2012, par Jizbo Jonez

  I have a bit of code that gets a video files duration, width, height and framerate which works fine for some videos -

  $output = `ffmpeg -i /var/thismovie.avi`;
  
  preg_match('/Duration: (.*?),.*?Video:.*?0x.*?([0-9]+)x([[0-9]+).*?([0-9]+) fps/i'
  
  ,$output , $result);

  The problem is there are other videos that give a slightly different output information, for example the above code works with this output -

  Input #0, avi, from '/var/www/vhosts/thissite.com/httpdocs/video1.avi':
  
  Duration: 00:00:10.76, start: 0.000000, bitrate: 5180 kb/s
  
  Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 50 tbc
  
  Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, s16, 128 kb/s

  but another video gives this info and will not give any results when used with the above code -

  Input #0, avi, from '/var/www/vhosts/thissite.com/httpdocs/video2.avi':
  
  Duration: 00:00:05.68, start: 0.000000, bitrate: 887 kb/s
  
  Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 640x272 [SAR 1:1 DAR 40:17], 25 tbr, 25 tbn, 25 tbc
  
  Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 128 kb/s

  The difference between the two outputs is in the Stream #0:0 part. The fist output shows 7 different pieces of information separated by a comma, the last output only shows 6 bits. The missing piece of info in the last output is the frame rate (fps) but apparently I can use the value for tbr instead.

  So my question is, how can I modify the code I am using to cover both types of outputs ?

• FFMpeg C++ How to create a filter with multiple outputs ?

  11 septembre 2020, par GoodSimon

  For example, we have one AVFrame with a size of 128x128 pixels and the task is to split the AVFrame into 4 parts (4 separate AVFrame). To do this, I fill the graph with filters using the avfilter_graph_parse2(...) function, and then call avfilter_graph_config(...).

  


  Let's start. Let's cut out the top left corner. To crop a frame, we need to use the crop filter, which means we initialize the AVFilterGraph graph with the line :

  


  buffer = width = 128: height = 128: pix_fmt = 2: time_base = 1/25, pixel_aspect = 128/64 [pad_in];
[pad_in] crop = w = 64: h = 64: x = 0: y = 0, buffersink;


  


  Everything works great ! Now let's try to make several outputs :

  


  buffer = width = 128: height = 128: pix_fmt = 2: time_base = 1/25, pixel_aspect = 128/64 [pad_in];
[pad_in] crop = w = 64: h = 64: x = 0: y = 0, buffersink;
[pad_in] crop = w = 64: h = 64: x = 64: y = 0, buffersink;
[pad_in] crop = w = 64: h = 64: x = 0: y = 64, buffersink;
[pad_in] crop = w = 64: h = 64: x = 64: y = 64, buffersink


  


  As you can see, we have one buffer for the input image, 4 crop filters for cutting each piece, and 4 buffersink filters for the output images. The call avfilter_graph_parse2(...) returns 0, which is good, but avfilter_graph_config() returns the error code -22 == AVERROR(EINVAL) and the message is output to the console : Input pad "default" with type video of the filter instance "Parsed_crop_3" of crop not connected to any source.

  


  I am asking for your help in creating a filter with multiple outputs.

  


• Trying to identify global metadata

  29 mai 2021, par the_steve_randolph

  I am pretty new to ffmpeg and using it to convert/change a large number of video files. I typically use VLC to find out some (all ?) of the information that I am interested in changing. But, one piece of information I can't seem to identify.

  


  I know that within a video file, each audio and video track have titles that I can change with ffmpeg. Also, I know that I can change the metadata tag "title" that would seem to encompass the entire file. This "title" value is displayed on the top line in VLC and displays in Windows Explorer in the "Title" column. This seems to be the same tag when you right-click on the file, click the "Details" tab, and, look at the "Title" tag under "Description".

  


  But, in some video files, in VLC I click on "Playback" and then "Title", there is different "title" information. Most of the time it is blank, but, other times there is one or two names that indicates it came from the "title" information of a DVD. That is, a DVD that has multiple titles (different/separate movies on the same disc). Well, I want to erase or change that "title" information, but, I cannot seem to determine where/how in ffmpeg to access it. This information is not shown with the "ffmpeg -i file.mp4" or "ffprobe -1 file.mp4".

  


  Since this "title" information is not directly related to a specific video track, I am assuming that it fits under the category of "global" metadata. Googling "ffmpeg global metadata tags", I can find some of the tags I typically change (i.e "frame height" and "frame width"), as well as the "title" that is the Windows Explorer "title" column. But, none of those search results mention this other "title" information/tag, or, that a DVD can have multiple titles that show up when converted to a MP4/MKV and viewed it in VLC.

  


  So, WTH is that tag name and is it something that ffmpeg can see and/or change ?