[FFmpeg-user] problem with fast seeking and splitting
Dear Experts, I'm trying to split an input file into 2 second chunks, transcode and assemble using a concat muxer. And experiencing two problems: major one: 1) when using ffmpeg -ss 00:00:08 -t 2 -i -c:v libx264 instead of seeking to second 8, ffmpeg seeks somewhere to second 15 or so. The first segments are correct, and then it start to go haywire. Using accurate seek ffmpeg -i -ss 00:00:08 -t 2 -c:v libx264 resolves the problem. But it is completely unusuble if you want to split the whole file. Minor one: 2) when concatenating the resulting files - there happens a noticeable break between the chunks. For both audio and video and is equal to 2 additional frame durations (e.g. prev chunk ends at 1.981333 and the next chunk (after concat) while it should start at 2.023000 actually starts at 2.095744 for 24 fps video, and for audio prev chunk ends at 1.927256 and starts at 2.023220 while it should start at 1.950476). adding all additional flags like copyts, copytb, enctimebase, vsync doesn't change anything. And it's really curious when using the hls demuxer - it splits the file accurately and fast, without these breaks. Can you please help me fix those two problems or suggest to understand which command like I could use to reproduce splitting behavior from the HLS demuxer? Thanks, Alexander // ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Single-field deinterlace with nnedi
On 4/30/22, Alexander Zhang wrote: >>> I'm trying to use nnedi to deinterlace a 29.97 fps video without >>> doubling the frame rate. I added the fields=a option which I thought was >>> supposed to make nnedi only use one of the two fields, but the output is >>> still 59.94 fps. Is this a bug or am I misunderstanding something? >>> >> >> Filter still produces same number of frames as input in field mode. >> Just every second frame is duplicated in output file because of fixed >> frame >> rate. > > So should I just drop every other frame with an fps filter to get half > the field rate? Nope, filtering is fine. It just tires to match output frame rate. ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-user] how to change the timecode without new encodig - some ideas and questions
Hi, I do have a bunch of Panasonic EVA1 clips, H.246 MOV and I like to change the timecode to a different value. Googling gave me some hint: ffmpeg -i file.MOV -map 0 -map -0:d -vcodec copy -timecode 16:21:08:10 fiel_newTC.MOV That command runs, but changes somehow the file: a) The size is slightly smaller, e.g. 246.939.019 vs. 247.060.908 Byte b) The codec is set to „XAVC Intra“ And e.g. VLC can't play that file and Adobe Premiere imports it as just an audio file. I'm on macOS 12.3.1 with ffmpeg version 5.0.1 What could be my problem? Thanks for any help, hint and suggestion . Regards . Götz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
