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

[Paul Gardiner]

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.
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>
> 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.