Thanks for the reference code. I would like to check it. Can you let me know what was the command line you had used to get it working. I was able to get blur video from the same command line in code as well. But not for slow down video. I was not able to slow down the complete video as well.
On Sat, Oct 15, 2022 at 8:06 PM <bsenft...@earthlink.net> wrote: > I have an ffmpeg video player that has the same AVFilter Graph text string > inputs as the command line ffmpeg. You could try looking at how I setup the > code and compare with what you’re doing. > > > > The key bits are in this file: > > > https://github.com/bsenftner/ffvideo/blob/master/ffvideolib_src/ffvideo_frameMgr.h > > > > There’s a frame manager class implementing frame filters starting around > line 110. > > > > Note, this does not do audio, but I’ve been told by a dev with a similar > playback library the audio handling is very similar. > > > > *From:* Libav-user <libav-user-boun...@ffmpeg.org> *On Behalf Of *Sushma > *Sent:* Saturday, October 15, 2022 7:36 AM > *To:* This list is about using libavcodec, libavformat, libavutil, > libavdevice and libavfilter. <libav-user@ffmpeg.org> > *Subject:* Re: [Libav-user] Slow down video > > > > Thanks for the reply. > > > > If pix_fmt=0 does not work, what are the other pixel formats that I can > use to achieve my requirement? > > > > >>atrim gets from [in1], i.e. buffer, while in the other version atrim is > connected to [0:a], i.e. a abuffer. > > > > Do you think I need to use it in a similar way in the API as well? If > possible, can you share a sample filter string that I could use? I tried > all possible ways but with no luck. > > > > Regards, > > Madhukar > > > > On Fri, Oct 14, 2022 at 6:43 PM Nicolas George <geo...@nsup.org> wrote: > > Sushma (12022-10-14): > > Hello All, > > > > I'm trying to use FFMPEG to slow down part of video and audio using C++ > > FFMPEG API. I was able to achieve it from the command line but however, > > argument parsing fails using api. > > > > Here is the command line input > > > > ffmpeg -i "inputvideo.mp4" -filter_complex > > > "[0:v]trim=0:2,setpts=PTS-STARTPTS[v1];[0:v]trim=2:10,setpts=2*(PTS-STARTPTS)[v2];[0:v]trim=10,setpts=PTS-STARTPTS[v3];[0:a]atrim=0:2,asetpts=PTS-STARTPTS[a1];[0:a]atrim=2:10,asetpts=PTS-STARTPTS,atempo=0.5[a2];[0:a]atrim=10,asetpts=PTS-STARTPTS[a3];[v1][a1][v2][a2][v3][a3]concat=n=3:v=1:a=1" > > -preset superfast -profile:v baseline output.mp4 > > > > Here is the filter string i used in avfilter_graph_parse() > > > > > buffer=video_size=1920x1080:pix_fmt=0:time_base=1/30:pixel_aspect=0/1:frame_rate=30/1 > > [in_1]; [in_1] trim = 0:2, setpts = PTS - STARTPTS [in_2]; [in_2] trim = > > 2:10, setpts = 2 * (PTS - STARTPTS)[in_3]; [in_3] trim = 10, setpts = > PTS - > > STARTPTS[in_4]; [in_1] atrim = 0:2, asetpts = PTS - STARTPTS[in_5]; > [in_5] > > atrim = 2:10, asetpts = PTS - STARTPTS, atempo = 0.5[in_6]; [in_6] atrim > = > > 10, asetpts = PTS - STARTPTS[in_7]; [in_1] [in_2] [in_5] [in_3] [in_6] > > [in_4] [in_7] concat = n = 3:v = 1 : a = 1 [result]; [result] buffersink > > > > Can anyone let me know where I'm wrong? What changes do I need to make in > > the filter string? Kindly help > > I see several issues: > > pix_fmt=0 will probably not work. > > atrim gets from [in1], i.e. buffer, while in the other version atrim is > connected to [0:a], i.e. a abuffer. > > You have several pads that are connected multiple times. > > Regards, > > -- > Nicolas George > _______________________________________________ > Libav-user mailing list > Libav-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/libav-user > > To unsubscribe, visit link above, or email > libav-user-requ...@ffmpeg.org with subject "unsubscribe". > > _______________________________________________ > Libav-user mailing list > Libav-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/libav-user > > To unsubscribe, visit link above, or email > libav-user-requ...@ffmpeg.org with subject "unsubscribe". >
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