[FFmpeg-user] libx264 options through FFmpeg

[Thomas Worth]

On Thu, Jun 30, 2011 at 3:22 AM, Tim Nicholson <tim.nicholson at bbc.co.uk> wrote:
> On 30/06/11 11:08, Tim Nicholson wrote:
>>
>> On 28/06/11 17:51, Thomas Worth wrote:
>>>
>>> On Tue, Jun 28, 2011 at 8:31 AM, Tim
>>> Nicholson<tim.nicholson at bbc.co.uk> wrote:
>>>>
>>>> On 22/06/11 06:43, Thomas Worth wrote:
>>>>>
>>>>> While I've historically used a standalone x264 binary to do encoding
>>>>> by piping yuv420p from FFmpeg, I thought I'd try libx264 through
>>>>> FFmpeg since it's certainly more convenient.
>>>>>
>>>>> [....]
>>>>>
>>>>> If I can safely pass all my options via -x264opts then I'll just use
>>>>> that from now on and disregard FFmpeg's x264 interface.
>>>>
>>>> But what about options that require colon delimited parameters
>>>> themselves
>>>> such as "--sar 1:1"?
>>>
>>> If I use a forward slash (sar=16/9), libx264 doesn't complain but it
>>> also doesn't use the supplied ratio. It seems to default to "1/1"
>>> every time.
>>
>> I have tried sar="1:1" and it hasn't complained about that.
>>
>> Howver it doesn't want to accept a profile specification. Using:-
>>
>> ffmpeg -i $in_file -vcodec libx264 -pix_fmt yuv420p -s 1920x1080 -an \
>> -x264opts bitrate=35000:preset=veryslow:tune=$tune:\
>> [...]
>>
>> I get a:-
>> "[libx264 @ 0x12e0960] bad value for 'preset': 'veryslow'"
>>
>> error. replace "veryslow" with whatever you like from the legal list.
>>
>
> Actually its worse than that, it also doesn't accept any of the --tune
> parameters, or seem to handle options that don't have values, e.g --tff

Yes, I had the same problems. What I found is that libx264 seems to
take all parameters through x264opts except the following:

preset
profile
tune

For some reason, it says "bad value for preset..." etc. But, and check
this out, if you supply any random value, you get the same error: "bad
value for 'giggity': 'goo'". So, it doesn't look like it even
recognizes it.

I do this:

ffmpeg -i file.mov -an -vcodec libx264 -preset medium -profile
baseline -tune film -x264opts $OPTS out.mp4

That seems to be working.

I just saw your email about parameters that don't take values, and
you're correct. tff=1 or aud=1 or 8x8dct=0 is the way you turn them on
or off.