[Libav-user] How to specify output format

Paul B Mahol onemda at gmail.com
Mon Jan 21 17:26:18 CET 2013


On 1/21/13, jim morgenstern <jmorgie at yahoo.com> wrote:
> Paul
> Thanks for the specifics.  I don't like headerless so .raw and .yuv are
> out.
>
> Hadn't heard of .nut;  I don't understand your comment about -vcodec etc.
> I am writing a C++ app not using the command line utilities.

I mean video codec should be set to rawvideo. And pixel format for that codec
should be same as one detected in input.

>
> So what all do I need to know about .nut?  Googled but cannot find any
> definitions or spec for the file.  Can you send a url?

You really should not need know anything, you just set output format to nut
and it is all what is needed. I doubt you want nut spec if you gonna use
libavformat to read nut files.

>
>
>
>> -----Original Message-----
>> From: libav-user-bounces at ffmpeg.org
>> [mailto:libav-user-bounces at ffmpeg.org]
>> On Behalf Of Paul B Mahol
>> Sent: Monday, January 21, 2013 10:41 AM
>> To: This list is about using libavcodec, libavformat, libavutil,
> libavdevice and
>> libavfilter.
>> Subject: Re: [Libav-user] How to specify output format
>>
>> On 1/21/13, jim morgenstern <jmorgie at yahoo.com> wrote:
>> > So what Specifically is the specific format extension that I give to
>> > ffmpeg that gives me the "raw video format" you cited?
>>
>> Headerless : .raw, .yuv (You need to remember pixel format and dimensions
>> stored in it)
>>
>> With headers : .nut (You must use -vcodec rawvideo and -pix_fmt same as
> your
>> input video
>>                      to keep video uncompressed)
>>     There are others like .avi, .. but they may not support pixel format
> of your
>> input video.
>>
>> >
>> >> -----Original Message-----
>> >> From: libav-user-bounces at ffmpeg.org
>> >> [mailto:libav-user-bounces at ffmpeg.org]
>> >> On Behalf Of Paul B Mahol
>> >> Sent: Monday, January 21, 2013 9:50 AM
>> >> To: This list is about using libavcodec, libavformat, libavutil,
>> > libavdevice and
>> >> libavfilter.
>> >> Subject: Re: [Libav-user] How to specify output format
>> >>
>> >> On 1/21/13, jim morgenstern <jmorgie at yahoo.com> wrote:
>> >> >>> where can I find the list of formats and their extensions?
>> >> >> In the source code
>> >> >
>> >> > Yes but the source code is hundreds of files;  can you tell me
>> >> > which one has the list and the mapping?
>> >> >
>> >> >
>> >> >> > .       What is your recommended format for uncompressed HD video
> ?
>> >> >>
>> >> >> libx264 is the state of the art encode
>> >> >
>> >> > But I do not want any encoding or compression:  I want flat file
>> >> > that can be read later on for more processing.  So is there a
>> >> > recommendation for a particular file format that does this?
>> >>
>> >> Depends on what you gonna use for more processing later.
>> >> Depending on available storage and CPU speed you could use raw video
>> >> formats...
>> >>
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >> -----Original Message-----
>> >> >> From: libav-user-bounces at ffmpeg.org
>> >> >> [mailto:libav-user-bounces at ffmpeg.org]
>> >> >> On Behalf Of Stefano Sabatini
>> >> >> Sent: Monday, January 21, 2013 7:50 AM
>> >> >> To: This list is about using libavcodec, libavformat, libavutil,
>> >> > libavdevice and
>> >> >> libavfilter.
>> >> >> Subject: Re: [Libav-user] How to specify output format
>> >> >>
>> >> >> In data Saturday 2013-01-19 01:55:22 -0500, Jim Morgenstern ha
>> >> >> scritto:
>> >> >> > I have C++ app [win 7]  that is reading and writing video/audio
>> > stream.
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > When I specify the output file as xxxx.MOV I am getting H264
>> >> >> > compressed video at 24 fps.
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > I want to have output as uncompressed at 30 or 60 fps according
>> >> >> > to the input.
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > Some simple [I hope] questions:
>> >> >> >
>> >> >> > .       What is [where can I find] the mapping between file name
>> >> > extension
>> >> >> > and format used?
>> >> >>
>> >> >> In the source code, or you can show the ".extensions" field for
>> >> >> all the
>> >> > registered
>> >> >> AVInput/OutputFormats.
>> >> >>
>> >> >> >
>> >> >> > .       Can I specify the output format I want rather than using
>> >> >> > av_guess_format ?  all the tutorials use guess
>> >> >>
>> >> >> Yes, you need to specify avformat_alloc_output_context2() and rely
>> >> >> on oformat/format_name parameters, or use av_guess_format().
>> >> >>
>> >> >> >
>> >> >> > .       What is your recommended format for uncompressed HD video
> ?
>> >> >>
>> >> >> libx264 is the state of the art encoder (but it has licensing
>> >> > constraints).
>> >> >> _______________________________________________
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>> >> >> Libav-user at ffmpeg.org
>> >> >> http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >
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