[FFmpeg-user] Please can someone tell me why this ffmpeg command stopped working

dE . de.techno at gmail.com
Sun Jan 29 01:00:36 CET 2012

On 01/29/12 00:29, Paul Gardiner wrote:
> On 28/01/2012 12:20, dE . wrote:
>> On 01/28/12 22:41, Paul Gardiner wrote:
>>> On 28/01/2012 16:49, Reindl Harald wrote:
>>>> Am 28.01.2012 17:33, schrieb Paul Gardiner:
>>>>> On 28/01/2012 16:24, Paul Gardiner wrote:
>>>>>> On 28/01/2012 16:10, Reindl Harald wrote:
>>>>>>> Am 28.01.2012 16:53, schrieb Paul Gardiner:
>>>>>>>> Can anybody see what is wrong with this:
>>>>>>>> /usr/bin/ffmpeg -f ac3 -ar 48000 -i /tmp/mythar4336/audout -f
>>>>>>>> rawvideo -top 1 -pix_fmt yuv420p -s 1440x1088 -r 25
>>>>>>>> -i /tmp/mythar4336/vidout -threads 2 -vf
>>>>>>>> crop=1440:1080:0:0,scale=1280:720 -vcodec libx264 -preset medium
>>>>>>>> -crf
>>>>>>>> 20.0
>>>>>>>> -bufsize 25000k -maxrate 20000k -aspect 16:9 -acodec copy -f mp4
>>>>>>>> /home/public/video/Archive/Horizon - Playing God.mp4
>>>>>>>> Until a recent ffmpeg update, it used to do exactly what I
>>>>>>>> wanted, but
>>>>>>>> now it produces the error message: "Option sample_rate not
>>>>>>>> found." I've
>>>>>>>> googled and found various references to people having to make sure
>>>>>>>> arguments are in the right order with later versions of ffmpeg, 
>>>>>>>> but
>>>>>>>> my command seems to obey the rules, plus attempts I have made to
>>>>>>>> reorder
>>>>>>>> have not helped.
>>>>>>> "-f ac3 -ar 48000 -i"
>>>>>>> why is "-ar" BEFORE the input file?
>>>>>>> in this case you set the parameter for the input instead the output
>>>>>> My thinking was that the input was 48kHz and I needed to tell ffmpeg
>>>>>> that information about the input. I guess that's showing my
>>>>>> misunderstanding about how it works.
>>>> i would say ffmpeg is knowing more about the input file as you and i
>>>> will
>>>> ever be able and there may be only very few cases where it needs help
>>>> the output should specifuied so exactly as possible if you nedd videos
>>>> palying in iPhone as example to make sure they are H264 BASELINE but
>>>> not the input (use the ffmpeg output to see what is really is *gg*)
>>>>>> Off to try the alteration now.
>>>>> Brilliant! It worked. I am again able to transcode my TV recordings.
>>>>> I guess I should also move the "-r 25" from before the second
>>>>> input-file argument. Is that right?
>>>> it is quite simple, all parameters before any file are taken as
>>>> params for exactly this one
>>> Yes that's completely plain from the documentation, but did you get
>>> my point that I didn't know whether -ar 48000 should be used to
>>> tell ffmpeg the sample rate of the input file I was supplying or
>>> whether it should be used to tell ffmpeg the sample rate I wanted
>>> in the output file. I know now of course with your help.
>>> Cheers,
>>> Paul.
>>> _______________________________________________
>>> ffmpeg-user mailing list
>>> ffmpeg-user at ffmpeg.org
>>> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>> Also, I don't think you should use maxrate, last time I checked it
>> didn't work with x264. Use -x264opts qp=<a value from 0 (lossless) to 60
>> (worst quality)> instead.
> Yes. I suspected that wasn't ideal. Isn't there another option like
> -preset that I should be using which sets a whole lot of limits in
> one go?
> P.


-preset is sort of the lossless compression level.

It includes -

ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, 
veryslow, placebo

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