Am So., 15. Dez. 2019 um 16:50 Uhr schrieb Mark Filipak <[email protected]>: > > I run this command: > ffmpeg -ss 30.0 -i %1 -hide_banner -filter:v idet -frames:v 900 -an -f > rawvideo -y NUL > to gather data on multimedia source files (passed in via %1).
When asking questions on this mailing list, please do not use -hide_banner (unless you want to report an issue with this option). > I've run it against a wide mix -- close to a hundred -- sources: > - 24 FPS, > - 25 FPS, > - soft telecined, > - hard telecined, and > - NTSC with embedded hard telecined (e.g., "Making of" documentaries). > I've included a typical output (with added line #s) at the bottom of > this message. > > Question: Is the output listing documented anywhere? > Of particular interest are: > - the meaning of "tbr" (line 04), > - the meaning of "tbc" (line 04), Different time bases, tbn is the container, tbc is codec iirc. > - the meaning of "dup" (line 18), This is a message from the ffmpeg executable to tell you how many frames were duplicated to get cfr output. > - why 'dup'+'drop'+'Neither'+'Top'+'Bottom' (lines 18 & 20) always > equals 901, and dup is not related to neither top and bottom (although the sum is related to your 900 request) You can use -vsync 0 for your use case, it will avoid the duplicate frames. > - why 'Neither'+'Top'+'Bottom' (line 20) totals 830 instead of 1660. I wrote originally: Because there are less input frames than output frames, this is related to the fact that your input are mpeg streams. But the answer is more likely: FFmpeg (and digital transcoders in general) doesn't know about fields, it can only work with frames. (This is also related to the specifications of sane video codecs.) Carl Eugen _______________________________________________ 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".
