Note that the video image will be stretched horizontally or vertically if the output width/height ratio is different from the ratio in the input file. Select the output video resolution with the video filter parameter: Set -q 2 to get a pretty high quality video bitrate. The -q parameter can also be used to control the quality of the video output. vcodec copy # for all versions of ffmpeg c:v copy # for newer versions of ffmpeg only This will override any encoding-related settings. Unfortunately, this parameter is not available in older versions of ffmpeg you can use -vcodec copy to copy over the video from the original file without re-encoding it. Set it closer to the original file's bitrate to reduce the amount of compression. Add this argument somewhere in the command, set off by spaces-for example, right before specifying the output file. Set the bitrate of the output file with the -b:v argument. To extract only the audio portion of a video, use the -vn parameter to indicate no video output: Using a small GOP value in step one makes this quick jump possible:įfmpeg -ss target-1 -i temp.MXF -ss 1 -q 2 -t duration_of_chunk out.mpg Here's one strategy for extracting video from MXF files that has worked:ġ) convert to a format that has a small GOP (group of pictures) value -g 1Īnd keep a high video bit rate ( -b:v) to keep detail in the video:įfmpeg -i my.MXF -g 1 -b:v 35000k temp.MXFĢ) seek in the temp.MXF file to just before your target start time for the extracted video - the first seek (ss) in this command jumps to 1 second before the target very quickly and the second seek steps over frames until it gets to exactly your target time. This command, for example, would extract a 1.5-second clip starting at 5.3 seconds into 'longfile.avi' and save it to 'shortfile.avi':įfmpeg -ss 00:00:05.30 longfile.avi -t 1.5 shortfile.avi To extract video from a certain time, use the -ss and -t flags to specify start time and duration, respectively:įfmpeg -ss HH:MM:SS INFILE -t DURATION OUTFILE 4 Changing the video resolution (scaling).

Php ffmpeg resize without stretching