After several tries, I noticed that doing : ffmpeg -i clip.ts -c copy -y -copyts -mpegts_copyts 1 -ss -14 clip-correct-pts.ts
shifts the pts without modifyijng the video. So I did 2 passes after retrieving the pts of the first frame to calculate the offset. On Fri, Feb 8, 2019 at 8:14 AM Gyan <[email protected]> wrote: > > > On 07-02-2019 03:47 AM, Julien De Luca wrote: > > Hello all, > > > > I'm trying to set the initial pkt_pts_time using output_ts_offset. On > > streams encoded using ffmpeg, it always sets the offset + 0.08s, which > is 2 > > frames. Here is the command I use : > > > > ``` > > ffmpeg -i input.ts -acodec aac -vcodec libx264 -f mpegts -preset veryfast > > -filter:v scale=640:-1 -framerate 25 -profile:v main -b:v 1200000 -level > > 3.1 -b:a 96000 -g 75 -bf 3 -output_ts_offset 10 -muxdelay 0 -muxpreload 0 > > output.ts > > ``` > > > > And the output from ffprobe for the first video frame : > > ``` > > { > > "media_type": "video", > > "stream_index": 0, > > "key_frame": 1, > > "pkt_pts": 907200, > > "pkt_pts_time": "10.080000", > > "pkt_dts": 907200, > > "pkt_dts_time": "10.080000", > > "best_effort_timestamp": 907200, > > "best_effort_timestamp_time": "10.080000", > > "pkt_duration": 3600, > > "pkt_duration_time": "0.040000", > > "pkt_pos": "1128", > > "pkt_size": "4872", > > "width": 640, > > "height": 360, > > "pix_fmt": "yuv420p", > > "sample_aspect_ratio": "1:1", > > "pict_type": "I", > > "coded_picture_number": 0, > > "display_picture_number": 0, > > "interlaced_frame": 0, > > "top_field_first": 0, > > "repeat_pict": 0, > > "chroma_location": "left" > > } > > ``` > > > > The input is a ts file from a segmented stream created using hls options > of > > ffmpeg. > > > > On another input created using AWS Mediaconvert, pkt_pts_time is set > > correctly, at exactly 10. > > > > Is there any known reason this may happen ? > > > > What's the output with > > ffmpeg -i input.ts -an -vcodec libx264 -f mpegts -preset veryfast > -filter:v scale=640:-1 -profile:v main -b:v 1200000 -level > 3.1 -g 75 -bf 3 -output_ts_offset 10 -muxdelay 0 -muxpreload 0 > output.ts > > Gyan > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
