#11080: FFmpeg timestamps do not consistently agree with packet timestamps
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Reporter: markfilipak | Owner: (none)
Type: defect | Status: new
Priority: normal | Component:
| undetermined
Version: unspecified | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by pdr0):
Replying to [comment:20 markfilipak]:
> Replying to [comment:14 pdr0]:
> > Ticket_11080.m2ts is the same problem as ticket #11055 - not a valid
stream
> >
> > Not cut/appended on IDR boundaries, no IDR pictures , decreasing
frame_num and decreasing POC violations in coded stream order
> >
> > eg.
> > Notice frame_num drops from 243 to 191
>
> The clip has only 97 frames.
>
> Notice that frame_num applies to slices. Notice that H.264 says what to
do with frame_num, but it never defines "frame_num".
Yes, if you look at the parser there are 4 slices per frame (as per the BD
specs) . The frame_num is wrong because it was improperly cut from a
longer segment with more frames (slices), as described in ticket 11055 .
Because there are no IDR frames or slices, there is no reset to frame_num
and you get discontinunities
"frame_num is used as an identifier for pictures "
https://patents.google.com/patent/US20140064363A1/en
" For each reference picture in H.264, there is a codeword frame_num that
acts as a label for the reference picture. The frame_num indicates the
decoding order and the frame_num must increase by 1 for each reference
picture in decoding order otherwise the bitstream is not compliant to the
standard."
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11080#comment:25>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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