#450(documentation:new): Specify the position of -isync more precisely
#450: Specify the position of -isync more precisely -------------------------------------+------------------------------------- Reporter: burek | Owner: stefano Type: | Status: new enhancement | Component: Priority: normal | documentation Version: | Keywords: unspecified | Blocking: Blocked By: | Analyzed by developer: 0 Reproduced by developer: 0 | -------------------------------------+------------------------------------- I've figured that the -isync option does not produce the same effect when placed in front of inputs, between the inputs and after the inputs. I just think it would be a good idea to put a little explanation in the documentation about the proper usage of that option. For example, these 2 examples produce different results: ffmpeg -f alsa -ac 1 -i hw:1 -isync -f video4linux2 -r 15 -s qqvga -i /dev/video0 -vcodec libx264 -preset ultrafast -g 15 -crf 20 -acodec aac -strict experimental -ar 44100 -ab 96k -ac 1 -f mpegts udp://192.168.25.101:10001 ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -r 15 -s qqvga -i /dev/video0 -isync -vcodec libx264 -preset ultrafast -g 15 -crf 20 -acodec aac -strict experimental -ar 44100 -ab 96k -ac 1 -f mpegts udp://192.168.25.101:10001 (the second example has -isync moved after the 2nd input) -- Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/450> FFmpeg <http://ffmpeg.org> FFmpeg issue tracker
#450: Specify the position of -isync more precisely -------------------------------------+------------------------------------- Reporter: burek | Owner: stefano Type: enhancement | Status: open Priority: normal | Component: Version: unspecified | documentation Keywords: | Resolution: Blocking: | Blocked By: Analyzed by developer: 0 | Reproduced by developer: 0 -------------------------------------+------------------------------------- Changes (by cehoyos): * status: new => open Comment: Is there any difference in behaviour noticeable (or even expected) between {{{ ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -r 15 -s qqvga -i /dev/video0 -isync -vcodec libx264 -preset ultrafast -g 15 -crf 20 -acodec aac -strict experimental -ar 44100 -ab 96k -f mpegts udp://192.168.25.101:10001 }}} and {{{ ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -r 15 -s qqvga -i /dev/video0 -vcodec libx264 -preset ultrafast -g 15 -crf 20 -acodec aac -strict experimental -ar 44100 -ab 96k -f mpegts udp://192.168.25.101:10001 }}} ? FFmpeg expects options that apply to inputs before the affected input, so I would assume that putting -isync before the output file (after all inputs) has no effect. -- Ticket URL: <https://avcodec.org/trac/ffmpeg/ticket/450#comment:1> FFmpeg <http://ffmpeg.org> FFmpeg issue tracker
#450: Specify the position of -isync more precisely -------------------------------------+------------------------------------- Reporter: burek | Owner: stefano Type: enhancement | Status: open Priority: normal | Component: Version: unspecified | documentation Keywords: | Resolution: Blocking: | Blocked By: Analyzed by developer: 0 | Reproduced by developer: 0 -------------------------------------+------------------------------------- Comment (by burek): In my case, the only time, when I succeeded to sync inputs, was when -isync param was after both inputs. Otherwise, it just wouldn't sync them (I didn't test what is the drift in each case, I just wanted both to be in sync). -- Ticket URL: <https://avcodec.org/trac/ffmpeg/ticket/450#comment:2> FFmpeg <http://ffmpeg.org> FFmpeg issue tracker
#450: Specify the position of -isync more precisely -------------------------------------+------------------------------------- Reporter: burek | Owner: stefano Type: enhancement | Status: closed Priority: normal | Component: Version: unspecified | documentation Keywords: isync | Resolution: fixed Blocking: | Blocked By: Analyzed by developer: 0 | Reproduced by developer: 0 -------------------------------------+------------------------------------- Changes (by cehoyos): * keywords: => isync * status: open => closed * resolution: => fixed Comment: The option was disabled in 15141f9 and deprecated in 67a6dac, the documentation was updated accordingly. -- Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/450#comment:3> FFmpeg <http://ffmpeg.org> FFmpeg issue tracker
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