[FFmpeg-devel] Fwd: ffmpeg -ss switch needs a verbose indication it´s actually skipping frames...

[Fernando Cassia]

Hi

I recently became aware of the very handy ?-ss? skip switch in ffmpeg
-previously I used to convert whole long videos then cut what I needed
- d?oh!-

While the current output might seem fine for very short skips, where
the skipping operation lasts only a few seconds, if I have a 60-min
long HD video and I just want ffmmpeg to convert the last 10 minutes,
that?s skipping 50 mins of source material, which ain?t fast.

In the current design, ffmpeg outputs something like this:

---
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit

...for tens of minutes... before getting to the point where it was
told to begin... wher output eventually changes to:

frame= ?926 fps= ?1 q=2.0 size= ? 24952kB time=30.86 bitrate=6622.8kbits/s
... and so on...

I first thought the feature was buggy, or that ffmpeg had entered a
loop due to wrong switches or something else....

So, don?t you think that when the -ss switch is used output should be
a little bit more verbose like:

Skiping to 00:50:00 ..... curent frame: x ? frames to go:y .....
Skiping to 00:50:00 ..... curent frame: x ? frames to go:y .....
Skiping to 00:50:00 ..... curent frame: x ? frames to go:y .....
Skiping to 00:50:00 ..... curent frame: x ? frames to go:y .....

and then when the start point is reached, switch to the conventional output...

frame= ?926 fps= ?1 q=2.0 size= ? 24952kB time=30.86 bitrate=6622.8kbits/s
... and so on...

My view is that showing
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit
frame= ? ?0 fps= ?0 q=0.0 size= ? ? ? 0kB time=10000000000.00 bitrate= ? 0.0kbit

is meaningless. Specially the part "time=10000000000.00"

Thoughts? comments? expletives? (j/k).

FC
PS: is there a project?s bugzilla where I could file this as a RFE?