Mpeg flow writes dummy data !

[tgamal]

When I run mpeg flow on a couple of my videos I see that it writes a lot of dummy data. So if you have 2 frames in my video I will see around 512 dummy vectors in between
'''
pts=0 frame_index=1 pict_type=I output_type=arranged shape=56x28 origin=video
pts=1 frame_index=-1 pict_type=? output_type=arranged shape=56x28 origin=dummy
pts=2 frame_index=-1 pict_type=? output_type=arranged shape=56x28 origin=dummy
#----
pts=512 frame_index=2 pict_type=P output_type=arranged shape=56x28 origin=video
'''
Is it something wrong with my videos ?

[Squolly]

I had a similar problem. It happens because of lines 310 and 312 in mpegflow.c:

Line 310: if(!prev.empty() && pts != prev.back().Pts + 1)
Line 312: for(int64_t dummy_pts = prev.back().Pts + 1; dummy_pts < pts; dummy_pts++)

In both cases it is assumed the pts of consecutive frames increases by 1 which is not always the case. It depends on time_base in AVStream and the frame rate aimed for.
I assume if you change the +1 into +512 in both lines (and dummy_pts+=512) it may work in your case (in addition you would have to change Line 126 in vis.cpp too). In my case I tried to replace +1 with a delta calculated cased on time_base and avg_frame_rate (I don't know if it works for all videos yet).

A change should also consider to adjust Line 154 in mpegflow.cpp to work in cases without pkt_pts and pkt_dts.

[rohit-gupta]

Has anyone resolved this issue ? It seems like a waste of memory to do this, and pointlessly requires us to filter the text file afterwards.