Michael Rampe
Forum Replies Created
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[Joseph Thompson] “Where can I download the most current windows version of FFmpeg?”
Check out https://ffmpeg.arrozcru.org/ as is linked from https://www.ffmpeg.org
Michael
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[Stan Juznitok] “Is there some option(s) that I should enable in ffmpeg that gives me the statistics on time needed to encode a file using different presets (e.g. veryslow, slow, medium, fast, faster…)”
Yes. It is the -benchmark option.
Use “1> benchmark.txt” to write it to a file.
Michael
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[Stan Juznitok] “I was wondering if there is a way to obtain the default parameter setting for ffmpeg when used for encoding with x264. For exmaple, if I encode a video using x264 and don’t specify the target bitrate, it encodes the video usually around 200kps, so target of 200kbps is probably set somewhere by default. Is there a way to obtain some kind of a list of all defaults for ffmpeg+x264.”
$ man ffmpeg
Where applicable, defaults are listed next to the options.
eg.
“‘-b bitrate’Set the video bitrate in bit/s (default = 200 kb/s). ”
x264 is a library used by FFmpeg and not part of the trunk. Where the options are mapped, FFmpeg defaults should carry across. Where they are not, you might have to look at the x264 manual.
$ x264 -h
Michael
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[Venkatesh Guptha] ”
i dont want duration, instead i need size of the output file (trancoded file) before transcode starts.”I interpreted “file length” as time. “file size” would have been clearer.
[Venkatesh Guptha] “Is there any formula to calculate it?”
Fairly straightforward.
bitrate/8*length(seconds)=size (in Bytes). Divide by 1024 for KB. Divide by 1024 again for MB. etc.
Of course, with most codecs, this will be approximate. Don’t forget to include the audio bitrate in your calculations, a common mistake.
Michael
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[Kosta smith] ” i just need to figure out how to compile my own windows version now”
…or try the *old* “movie” filter syntax.
Michael
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[Venkatesh Guptha] ” I want to calculate the transcoded file length before transcode starts.”
ffmpeg -i [inputfile]
This will give you the duration of the input.
Also have a look at FFprobe.
Michael
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[Kosta smith] “can anyone help?”
Maybe. Which version of FFmpeg are you using?
The syntax of the “movie” filter has changed recently and it looks like you are using the new syntax. The old syntax looks something like “movie=0:png:watermark.png”
Michael
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[derek winnicki] “Am I missing part of the libavformat library or am I just giving the makefile the wrong path?”
[derek winnicki] “which gives me the impression that I in fact DO have these libraries. Please help!”
Not really sure *where* Mac ports puts all of it’s stuff. Try to compile FFmpeg from latest source. This way you will definately know where they are.
Michael
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[John Coulson] ” I would like to be able to deinterlace them.”
Use “-deinterlace” in your encode string. You could also investigate yadif which is another method.
[John Coulson] “Is there a way to do so with FFmpeg, with the proviso that the quality of the resulting, deinterlaced, file should not suffer?”
ALL deinterlacing = quality loss. Basically, at the simplest level you are throwing away one field and duplicating the other so getting half vertical resolution.
[John Coulson] “Also, would it be possible for the output file to be in M2TS format as well?”
Use “-f mpegts” in your encode string.
Michael
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[jake hi] “Great! BUT, the second video stream was converted into an mpeg4 stream (and was in 200k b/s) completely avoiding my “-vcodec copy” option.”
When using new video you have to specify the encoding setting just before it (and after the output file).
So instead of:
ffmpeg -y -i videout1.mp4 -i videout2.mp4 -vcodec copy -acodec copy -vcodec copy -acodec copy videout12.mp4 -newvideo
try
ffmpeg -y -i videout1.mp4 -i videout2.mp4 -vcodec copy -acodec copy videout12.mp4 -vcodec copy -acodec copy -newvideo
Michael