Changes between Version 14 and Version 15 of Seeking


Ignore:
Timestamp:
Sep 7, 2014, 1:13:52 PM (12 years ago)
Author:
c-14
Comment:

Fix inconsistency between seek time in command and seek time in text.

Legend:

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  • Seeking

    v14 v15  
    33= Introduction =
    44
    5 If you need to extract only a specific part of your input, you'll need to use the seeking option to get to that specific part in the input first. [http://ffmpeg.org/ffmpeg.html#Main-options The parameter -ss] is used to seek into the input and it can be used in several ways. 
     5If you need to extract only a specific part of your input, you'll need to use the seeking option to get to that specific part in the input first. [http://ffmpeg.org/ffmpeg.html#Main-options The parameter -ss] is used to seek into the input and it can be used in several ways.
    66
    77= Fast seeking =
    … …  
    1515[[Image(out.jpg)]]
    1616
    17 This example will produce one image frame (out1.jpg) at the third minute from the beginning of the movie. The input will be parsed '''using keyframes''', which is '''very fast'''. As of FFmpeg 2.1, when transcoding with `ffmpeg` (i.e. not [https://ffmpeg.org/ffmpeg.html#Stream-copy stream copying]), `-ss` is now accurate even when used as an input option. Previous behavior can be restored with the `-noaccurate_seek` option.
     17This example will produce one image frame (out1.jpg) at the twenty-third minute from the beginning of the movie. The input will be parsed '''using keyframes''', which is '''very fast'''. As of FFmpeg 2.1, when transcoding with `ffmpeg` (i.e. not [https://ffmpeg.org/ffmpeg.html#Stream-copy stream copying]), `-ss` is now accurate even when used as an input option. Previous behavior can be restored with the `-noaccurate_seek` option.
    1818
    1919= Slow seeking =
    … …  
    2727[[Image(out.jpg)]]
    2828
    29 This example will also produce one image frame (out2.jpg) precisely at the third minute from the beginning of the movie.
     29This example will also produce one image frame (out2.jpg) precisely at the twenty-third minute from the beginning of the movie.
    3030
    3131Here, the input will be decoded until it reaches the position given by `-ss`. This will be done  '''very slowly''', frame by frame. As of FFmpeg 2.1, the main advantage is that when applying filters to the output stream, the timestamps aren't reset prior to filtering (i.e. when [https://trac.ffmpeg.org/wiki/HowToBurnSubtitlesIntoVideo burning subtitles into a video], you don't need to modify the subtitle timestamps), but the drawback is that it will take a lot of time until it finally reaches that time point. The bigger the seeking time is, the longer you will have to wait.