[MPlayer-users] Screenshot from specific frame number

[Marlon Smith]

Hi everyone,

I have a raw h.264 video file, and I'd like to take a screenshot of one
of the frames. I know the video is encoded at 30fps. Normally, I can
use the -ss option to seek to the time location I want, but since this
is a raw h.264 file that doesn't seem to be an option.

Can anyone think of a way for me to seek to a specific frame, and take a
screenshot of that frame? That way I can still take a screenshot at the
time I want.

Thanks!

Marlon
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[Onur Küçük]

On Sun, 04 Mar 2012 15:26:49 -0800
Marlon Smith <marlon....@gmail.com> wrote:

> Hi everyone,
>
> I have a raw h.264 video file, and I'd like to take a screenshot of
> one of the frames. I know the video is encoded at 30fps. Normally,
> I can use the -ss option to seek to the time location I want, but
> since this is a raw h.264 file that doesn't seem to be an option.
>
> Can anyone think of a way for me to seek to a specific frame, and
> take a screenshot of that frame? That way I can still take a
> screenshot at the time I want.

Using -vo with an image format may help, that way you can take images
and select which one you want from them. See man page and

mplayer -vo help

--
Onur Küçük Knowledge speaks,
<onur.--.-.delipenguen.net> but wisdom listens

[Marlon Smith]

Hi Onur, thanks for the quick reply. I've been doing this to get a
screenshot from an avi video file:

mplayer input_file.avi -nosound -ss 00:00:10 -vo png -frames 1

and it does exactly what I want. It just doesn't work for raw h.264
files since I can't seek to a time location. In the example above, I'd
love to just replace the 00:00:10 with frame #300, but mplayer doesn't
seem to give me that option.

Marlon

[Marlon Smith]

Does anyone else have any thoughts on this? I'd really appreciate it.

Marlon

On Mon, 2012-03-05 at 01:31 +0200, Onur Küçük wrote:

[Lobster]

On 7/03/2012 8:15 a.m., Marlon Smith wrote:
> Does anyone else have any thoughts on this? I'd really appreciate it.
>
> Marlon
>
> On Mon, 2012-03-05 at 01:31 +0200, Onur Küçük wrote:
>
>> On Sun, 04 Mar 2012 15:26:49 -0800
>> Marlon Smith<marlon....@gmail.com> wrote:
>>
>>> Hi everyone,
>>>
>>> I have a raw h.264 video file, and I'd like to take a screenshot of
>>> one of the frames. I know the video is encoded at 30fps. Normally,
>>> I can use the -ss option to seek to the time location I want, but
>>> since this is a raw h.264 file that doesn't seem to be an option.
>>>
>>> Can anyone think of a way for me to seek to a specific frame, and
>>> take a screenshot of that frame? That way I can still take a
>>> screenshot at the time I want.

You could try using the framestep vf,
i.e `mplayer -nosound -benchmark -vf framestep=2800 -frames 1 -vo png
input.h264`

be aware, every frame until the frame you want will be decoded,
meaning if it is a long way into the file it may take a while.
I have not tested this myself so cant confirm it will work.

[Marlon Smith]

Thanks Lobster! That was exactly what I needed; I can deal with it
taking a minute to speed through the file.

Much appreciated!

Marlon

[Marlon Smith]

Hi everyone,

In the version of mplayer I'm running in Linux, I use the following
command to create a raw h.264 file, which mplayer tells me is an h.264
elementary stream file when I play it back:

mencoder input_filename -nosound -of rawvideo -ofps 30 -vf harddup -ovc
x264 -x264encopts bframes=0 -o output_filename

When I run the same command in Windows (I've tried with several of the
precompiled Windows binaries available), mplayer tells me:

libavformat file format detected

instead of what it said with the file generated in Linux, which is:

H264-ES file format detected

Does anyone know if there's a parameter I'm missing to specify that I
want mencoder to create an elementary stream? I'm converting the files
for some custom hardware, and it's very picky about what it will play.

Thanks!

Marlon