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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>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.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The key bits are in this file:<o:p></o:p></p><p class=MsoNormal><a href="https://github.com/bsenftner/ffvideo/blob/master/ffvideolib_src/ffvideo_frameMgr.h">https://github.com/bsenftner/ffvideo/blob/master/ffvideolib_src/ffvideo_frameMgr.h</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>There’s a frame manager class implementing frame filters starting around line 110. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>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. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b>From:</b> Libav-user <libav-user-bounces@ffmpeg.org> <b>On Behalf Of </b>Sushma<br><b>Sent:</b> Saturday, October 15, 2022 7:36 AM<br><b>To:</b> This list is about using libavcodec, libavformat, libavutil, libavdevice and libavfilter. <libav-user@ffmpeg.org><br><b>Subject:</b> Re: [Libav-user] Slow down video<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Thanks for the reply.<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>If <span style='color:#500050'>pix_fmt=0 does not work, what are the other pixel formats that I can use to achieve my requirement?</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>>>atrim gets from [in1], i.e. buffer, while in the other version atrim is<br>connected to [0:a], i.e. a abuffer.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>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.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Regards,<o:p></o:p></p></div><div><p class=MsoNormal>Madhukar <o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Fri, Oct 14, 2022 at 6:43 PM Nicolas George <<a href="mailto:george@nsup.org">george@nsup.org</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><p class=MsoNormal>Sushma (12022-10-14):<br>> Hello All,<br>> <br>> I'm trying to use FFMPEG to slow down part of video and audio using C++<br>> FFMPEG API. I was able to achieve it from the command line but however,<br>> argument parsing fails using api.<br>> <br>> Here is the command line input<br>> <br>> ffmpeg -i "inputvideo.mp4" -filter_complex<br>> "[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"<br>> -preset superfast -profile:v baseline output.mp4<br>> <br>> Here is the filter string i used in avfilter_graph_parse()<br>> <br>> buffer=video_size=1920x1080:pix_fmt=0:time_base=1/30:pixel_aspect=0/1:frame_rate=30/1<br>> [in_1]; [in_1] trim = 0:2, setpts = PTS - STARTPTS [in_2]; [in_2] trim =<br>> 2:10, setpts = 2 * (PTS - STARTPTS)[in_3]; [in_3] trim = 10, setpts = PTS -<br>> STARTPTS[in_4]; [in_1] atrim = 0:2, asetpts = PTS - STARTPTS[in_5]; [in_5]<br>> atrim = 2:10, asetpts = PTS - STARTPTS, atempo = 0.5[in_6]; [in_6] atrim =<br>> 10, asetpts = PTS - STARTPTS[in_7]; [in_1] [in_2] [in_5] [in_3] [in_6]<br>> [in_4] [in_7] concat = n = 3:v = 1 : a = 1 [result]; [result] buffersink<br>> <br>> Can anyone let me know where I'm wrong? What changes do I need to make in<br>> the filter string? Kindly help<br><br>I see several issues:<br><br>pix_fmt=0 will probably not work.<br><br>atrim gets from [in1], i.e. buffer, while in the other version atrim is<br>connected to [0:a], i.e. a abuffer.<br><br>You have several pads that are connected multiple times.<br><br>Regards,<br><br>-- <br> Nicolas George<br>_______________________________________________<br>Libav-user mailing list<br><a href="mailto:Libav-user@ffmpeg.org" target="_blank">Libav-user@ffmpeg.org</a><br><a href="https://ffmpeg.org/mailman/listinfo/libav-user" target="_blank">https://ffmpeg.org/mailman/listinfo/libav-user</a><br><br>To unsubscribe, visit link above, or email<br><a href="mailto:libav-user-request@ffmpeg.org" target="_blank">libav-user-request@ffmpeg.org</a> with subject "unsubscribe".<o:p></o:p></p></blockquote></div></div></body></html>