[FFmpeg-user] warning: first frame is no keyframe

tank pranav akshar_tank at yahoo.com
Thu Apr 12 13:15:38 CEST 2012


ffmpeg -filters

By applying above command , if you dont find filter "ashowinfo" in the filter list then , definitely you dont have that filter installed in your ffmpeg installation.

So, first verify that thing first.

Regards.


________________________________
 From: Shaily Athghara <shaily.athghara at gmail.com>
To: FFmpeg user questions and RTFMs <ffmpeg-user at ffmpeg.org> 
Sent: Thursday, April 12, 2012 3:33 PM
Subject: Re: [FFmpeg-user] warning: first frame is no keyframe
 
Thanks Pranav

Now I could able to find the I-frame by executing the command

ffmpeg -i file.ts  -vf   select='eq(pict_type\,I)'  -f  image2
images%05d.jpeg

But my requirement was : I have a raw file and a wav file which needs to be
encoded and output an flv,the genrated flv has both the video and audio
content but the issue was the initial portion of the video was grayed out.
So by applying the above logic I can get the I- frame from raw file and can
output an flv file (without gray )which is perfectly alright.But now the
next task is to sync the audio and video as I am extracting the audio from
wav file, If I am cutting some frame from the raw file I need to cut some
from wav and produce the flv file so that the video and audio will be in
sync.

To get this I thought of cutting the video based on the time stamp and
those valu    es I can get by executing the command "showinfo" of ffmpeg

./ffmpeg -i 1.h263 -af showinfo  -f flv  test_cut2.flv 2>list.txt

Is there any way so that I can get the same kind of information from wav
file and extract the audio.

"ashowinfo" of ffmpeg displays all the credentials of audio, but I couldn't
able to execute this as it is throwing some errors.

Please suggest am I doing the right approach or there is other way to deal
with that.

Thanks,
Shaily




On Wed, Apr 11, 2012 at 5:52 PM, tank pranav <akshar_tank at yahoo.com> wrote:

> Well, I dont know about this has got fixed or not.............. but
>
>
> to get all I frames exist in the video this is the command.
>
> ffmpeg -i file.ts  -vf   select="eq(pict_type\,PICT_TYPE_I)"  -f  image2
> images%05d.jpeg
>
> So, now what ever first frame you will get from above command , that will
> be your first I frame.
>
> so you need to do some prgramming , so that ffmpeg should come to know
> that from first I frame it has to start decoding and generating pictures.
>
> Regards,
> pranav.
>
>
>
> ________________________________
>  From: Shaily Athghara <shaily.athghara at gmail.com>
> To: FFmpeg user questions and RTFMs <ffmpeg-user at ffmpeg.org>
> Sent: Wednesday, April 11, 2012 5:34 PM
> Subject: Re: [FFmpeg-user] warning: first frame is no keyframe
>
> But this issue seems to be fixed in the latest release of ffmpeg.Please
> suggest some ffmpeg command so that I can extract the I frames by using
> this .
>
> I have downloaded dvbcut-0.5.4 but when I am executing the command "make"
> its throwing the error
>
> dvbcut-0.5.4]# make
> scons  \
>
> make: scons: Command not found
> make: *** [build] Error 127
>
>
> On Wed, Apr 11, 2012 at 4:17 PM, tank pranav <akshar_tank at yahoo.com>
> wrote:
>
> > when ever any video you decode , if that video starts with partial GOP
> > then its not possible to decode that kind of GOP. Take an example of
> let's
> > say , if any video starts with B or P frame then this kind of frames are
> > not possible to decode that is why ffmpeg is giving gray frames.
> >
> > Now what is the solution of that , you start decoding you video when u
> > encounter first I frame. so from there after , you will get whole frames
> > proper. ( thati s done by dvbcut software , if you are not aware about
> this
> > software then try once by downloading it ).
> >
> >
> >
> >
> > ________________________________
> >  From: Shaily Athghara <shaily.athghara at gmail.com>
> > To: ffmpeg-user at ffmpeg.org
> > Sent: Wednesday, April 11, 2012 4:11 PM
> > Subject: [FFmpeg-user] warning: first frame is no keyframe
> >
> > Thanks Carl,
> >
> > After executing the following command
> >
> > ./ffmpeg -r 6.5 -f h263 -i 1.raw -i 4.wav -y -f flv -ar 11025 output.flv
> >
> > It outputs the correct number of frames (frame=189) but started giving
> the
> > same warning
> >
> > "warning: first frame is no keyframe" and the initial frame are grayed
> out.
> >
> > ./ffmpeg -r 6.5 -f h263 -i 1.raw -i 4.wav -y -f flv -ar 11025 output.flv
> > ffmpeg version 0.10.2.git Copyright (c) 2000-2012 the FFmpeg developers
> >   built on Apr 11 2012 07:33:31 with gcc 4.1.2 20080704 (Red Hat
> 4.1.2-44)
> >   configuration:
> >   libavutil      51. 46.100 / 51. 46.100
> >   libavcodec     54. 14.101 / 54. 14.101
> >   libavformat    54.  3.100 / 54.  3.100
> >   libavdevice    53.  4.100 / 53.  4.100
> >   libavfilter     2. 67.101 /  2. 67.101
> >   libswscale      2.  1.100 /  2.  1.100
> >   libswresample   0. 10.100 /  0. 10.100
> > [h263 @ 0x1cdac20] warning: first frame is no keyframe
> > [h263 @ 0x1ccc4e0] max_analyze_duration 5000000 reached at 5005000
> > [h263 @ 0x1ccc4e0] Estimating duration from bitrate, this may be
> inaccurate
> > Input #0, h263, from '1.raw':
> >   Duration: N/A, bitrate: N/A
> >     Stream #0:0: Video: h263, yuv420p, 352x288 [SAR 12:11 DAR 4:3], 29.97
> > fps, 29.97 tbr, 1200k tbn, 29.97 tbc
> > [wav @ 0x1e89be0] max_analyze_duration 5000000 reached at 5120000
> > Input #1, wav, from '4.wav':
> >   Duration: 00:00:13.68, bitrate: 64 kb/s
> >     Stream #1:0: Audio: pcm_alaw ([6][0][0][0] / 0x0006), 8000 Hz, 1
> > channels, s16, 64 kb/s
> > [buffer @ 0x1cdb3e0] w:352 h:288 pixfmt:yuv420p tb:1/1000000 sar:12/11
> > sws_param:flags=2
> > Output #0, flv, to 'output.flv':
> >   Metadata:
> >     encoder         : Lavf54.3.100
> >     Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 352x288
> [SAR
> > 12:11 DAR 4:3], q=2-31, 200 kb/s, 1k tbn, 29.97 tbc
> >     Stream #0:1: Audio: adpcm_swf ([1][0][0][0] / 0x0001), 11025 Hz, 1
> > channels, s16, 44 kb/s
> > Stream mapping:
> >   Stream #0:0 -> #0:0 (h263 -> flv)
> >   Stream #1:0 -> #0:1 (pcm_alaw -> adpcm_swf)
> > Press [q] to stop, [?] for help
> > [h263 @ 0x1cdac20] warning: first frame is no keyframe
> > [h263 @ 0x1cdac20] concealing 308 DC, 308 AC, 308 MV errors
> > frame=  189 fps=0.0 q=7.5 Lsize=     342kB time=00:00:06.43 bitrate=
> > 434.6kbits/s
> > video:259kB audio:75kB global headers:0kB muxing overhead 2.359965%
> >
> > I tried the next option as well renaming 1.raw to 1.h263 but this also
> > gives the same output.
> > Also notice some more messages like "max_analyze_duration 5000000 reached
> > at 5005000" and " Estimating duration from bitrate, this may be
> > inaccurate"  not sure whether these are errors or just info messages.
> > _______________________________________________
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> > ffmpeg-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
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> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
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