We encoded an mp4 into segmented DASH with a single 3Mbps profile. We manually edited the MPD to expose a 1.5Mbps profile (no segments exist for this profile). We built a small app to transcode on-the-fly any request for a 1.5Mbps profile. We do this by concatenating the init segment and m4s 3Mbps segment for the given segment request and then transcode to 1.5Mbps.
Requests for any segment other than the first are not playable. Inspecting these segments shows the PTS is always zero. In other words, when the mp4 is generated and scaled to 1.5Mbps, the PTS is not preserved. We have tried many parameter options (copyts, genpts, igndts) to no success . The setpts option is only used for adjusting the incoming PTS to do different effects, so it seems there is no way to affect the output PTS. This can be tested on the command line by concatenating multiple scaled init and m4s segments together. Example command line to produce and init and m4s output: ffmpeg -i BigBuckBunny.mp4 -an -copyts -vsync passthrough -ss "00:00:15" -t 5 -vf "scale=-2:480" -f dash manifest.mpd Any suggestions and advice are appreciated. thanks chris _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
