[Libav-user] How to specify output format
Paul B Mahol
onemda at gmail.com
Mon Jan 21 21:53:46 CET 2013
On 1/21/13, jim morgenstern <jmorgie at yahoo.com> wrote:
> So this is the piece to the puzzle I am missing:
>
> * where does one set the output pixel format / video codec to
> CODEC_ID_RAWVIDEO ?
> I have
>> > m_pOutputFormat = av_guess_format(NULL, filename, NULL);
>> > m_pFormatContext = avformat_alloc_context();
>> > m_pFormatContext->oformat = m_pOutputFormat;
>
> So after I get a format context then I can go in and tweak the various
> fields?
m_pFormatContext->oformat->video_codec = CODEC_ID_RAWVIDEO.
When initialzing encoder you specify pix_fmt: example:
avctx->pix_fmt = PIX_FMT_YUV420P;
There is example code:
http://git.videolan.org/?p=ffmpeg.git;a=blob;f=doc/examples/muxing.c
> Sure wish someone would write a book
>
> Thanks
>
>
>
>> -----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 1:06 PM
>> 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:
>> > Paul -- couple of problems
>> >
>> > I did as you suggested and specified the output file as: *.nut
>> > ** ffmpeg associates the MPEG4 codec with this output and I want
>> > uncompressed
>> > ** the audio stream bombs
>> >
>> > Thanks for any help you can provide
>>
>> I said you must set video codec to rawvideo aka CODEC_ID_RAWVIDEO.
>>
>> >
>> > Here is a code snippet, then screen output from ffmpeg:
>> > =========
>> >
>> > m_pOutputFormat = av_guess_format(NULL, filename, NULL);
>> > m_pFormatContext = avformat_alloc_context();
>> > m_pFormatContext->oformat = m_pOutputFormat;
>> > _snprintf_s(m_pFormatContext->filename,
>> > sizeof(m_pFormatContext->filename), "%s", filename);
>> >
>> > // add the audio and video streams using the default format codecs and
>> > initialize the codecs.
>> > m_pAudioStream = NULL;
>> > if (m_pOutputFormat->audio_codec != CODEC_ID_NONE)
>> > {
>> > m_pAudioStream = add_audio_stream(m_pFormatContext,
>> > m_pOutputFormat->audio_codec, channels);
>> > }
>> > // and the abort comes from add_audio_stream ==================
>> >
>> > Starting MediaFileIO for D:\Data\Solavei.mov
>> >
>> > [mov,mp4,m4a,3gp,3g2,mj2 @ 00ad3320] Stream #1: not enough frames to
>> > estimate ra te; consider increasing probesize
>> > [mov,mp4,m4a,3gp,3g2,mj2 @ 00ad3320] Stream #2: not enough frames to
>> > estimate ra te; consider increasing probesize
>> >
>> > Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\Data\Solavei.mov':
>> > Metadata:
>> > major_brand : qt
>> > minor_version : 537199360
>> > compatible_brands: qt
>> > creation_time : 2012-07-12 23:41:43
>> > Duration: 00:00:11.81, start: 0.000000, bitrate: 598161 kb/s
>> > Stream #0:0(eng): Video: v210 (v210 / 0x30313276), yuv422p10le,
>> > 1280x720, 59
>> > 6600 kb/s, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc
>> > Metadata:
>> > creation_time : 2012-07-12 23:41:43
>> > handler_name : Apple Alias Data Handler
>> > Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz,
>> > stereo, s1 6, 1536 kb/s
>> > Metadata:
>> > creation_time : 2012-07-12 23:41:43
>> > handler_name : Apple Alias Data Handler
>> > Stream #0:2(eng): Data: none (tmcd / 0x64636D74)
>> > Metadata:
>> > creation_time : 2012-07-12 23:42:01
>> > handler_name : Apple Alias Data Handler
>> > timecode : 00:00:28;11
>> >
>> >
>> > Starting MediaFileIO for => D:\Data\TestSol.nut Output #0, nut, to
>> > 'D:\Data\TestSol.nut':
>> > Stream #0:0: Video: mpeg4, yuv420p, 1280x720, q=2-31, 5942 kb/s,
>> > 90k tbn, 29 tbc
>> > Stream #0:1: Audio: vorbis, 44100 Hz, 1 channels, s16, 64 kb/s
>> > [libvorbis @ 054e20c0] Specified sample_fmt is not supported.
>> >
>> > File Initialization Exception: output !!
>> > MediaFileWriter::open_audio: Could not open audio codec //this is my
> app
>> > error message
>>
>> You want to store audio? If yes. What codec?
>>
>>
>> >
>> >
>> >
>> >
>> >
>> >> -----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 11:26 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:
>> >> > 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).
>> >> >> >> >> _______________________________________________
>> >> >> >> >> Libav-user mailing list
>> >> >> >> >> Libav-user at ffmpeg.org
>> >> >> >> >> http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >> >> >
>> >> >> >> > _______________________________________________
>> >> >> >> > Libav-user mailing list
>> >> >> >> > Libav-user at ffmpeg.org
>> >> >> >> > http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >> >> >
>> >> >> >> _______________________________________________
>> >> >> >> Libav-user mailing list
>> >> >> >> Libav-user at ffmpeg.org
>> >> >> >> http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >> >
>> >> >> > _______________________________________________
>> >> >> > Libav-user mailing list
>> >> >> > Libav-user at ffmpeg.org
>> >> >> > http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >> >
>> >> >> _______________________________________________
>> >> >> Libav-user mailing list
>> >> >> Libav-user at ffmpeg.org
>> >> >> http://ffmpeg.org/mailman/listinfo/libav-user
>> >> >
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