[FFmpeg-user] flag YUV input as interlaced

Mark Himsley mark at mdsh.com
Thu May 12 17:17:43 CEST 2011


On 12/05/11 16:03, bouke wrote:
> ----- Original Message -----
> From: "Mark Himsley"<mark at mdsh.com>
> To: "FFmpeg user questions and RTFMs"<ffmpeg-user at ffmpeg.org>
> Sent: Thursday, May 12, 2011 4:51 PM
> Subject: Re: [FFmpeg-user] flag YUV input as interlaced
>
>
>> On 12/05/11 14:11, bouke wrote:
>>>
>>> ----- Original Message -----
>>> From: "Mark Himsley"<mark at mdsh.com>
>>> To: "FFmpeg user questions and RTFMs"<ffmpeg-user at ffmpeg.org>
>>> Sent: Thursday, May 12, 2011 2:13 PM
>>> Subject: [FFmpeg-user] flag YUV input as interlaced
>>>
>>>
>>>> Imagine I am using FFmpeg to read a raw YUV file. How do I flag that
>>>> input
>>>> file as interlaced so that interlaced aware filters process the stream
>>>> correctly?
>>>>
>>>> For instance:
>>>>    I have an SD PAL sized yvyu422 file that I know is top-field-first
>>>>    I want to output that as PAL DV 25, which is bottom-field-first
>>>>
>>>> I expect to use a command like like this:
>>>>
>>>> ffmpeg -f rawvideo -r 25 -s 720x576 -pix_fmt yuyv422 -i
>>>> input.yvyu422 -vf
>>>> fieldorder=bff -vcodec dvvideo -pix_fmt yuv420p -y output.mov
>>>
>>> Normally you put the known input specs before the input file, as in your
>>> example.
>>> So did you test
>>>    ffmpeg -f rawvideo -r 25 -s 720x576 -pix_fmt yuyv422  -vf
>>> eldorder=tff   -i input.yvyu422 -vf fieldorder=bff -vcodec
>>> dvvideo -pix_fmt
>>> yuv420p -y output.mov
>>>
>>> ?
>>
>> Hi Bouke,
>>
>> The -vf command is defining a filter, not setting switches on a file, so
>> that command does not work.
>
> Doh!
> Note to self, first think, then post....
> Dirty trick, if you can spare a line, you could crop off one line at the
> top, and pad one line at the bottom.
> That switches field dominance as well.

Hi Bouke,

That is true, but I wrote the fieldorder filter to do a _slightly_ 
better job then that (it fills the blank line created by the pad with 
roughly the right video data and only does the shift up/down it its 
required).

What I want to do, though, is to set a flag like -s, -r and -pix_fmt 
that sets the interlaced flag and tff flag on -f rawvideo media before 
the video hits the filter chain.

I just assumed I'd missed something. Perhaps I need to patch ffmpeg instead.

Thanks :-)


> Bouke
>
>
>> Thanks though.
>>
>>> Bouke
>>>
>>>> But, since the input file is not flagged as interlaced the fieldorder
>>>> filter cannot do it's job.
>>>>
>>>> Thanks.
>>>>
>>>> --
>>>> Mark



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