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One of your new releases
said it has this feature fixed: "Video and audio
synchronization problem for MPEG files with video PTS jumps.
(BUG)" Can you please explain what does it mean? Will it
restamp PTS/DTS when I concatenate few MPEG files together?
In many MPEG hardware and
software encoders, the system will drop video frames when it
cannot keep up with a real time video input. This could be
caused by an insufficient CPU/DSP processor power, temporary
memory bandwidth shortage, temporary disk access error,
system/disk/memory buffer full, or others. When this occurs,
the encoder will introduce a PTS time jump to the presentation
time of the next image, while keeping the audio continuous which
is less likely to have the same problems as those of the video
and which is also more noticeable if a sound drop occurred.
Those video PTS jumps are encoded in the packet headers as a
multiplexed MPEG stream. Also, the PTS time codes may start at
any value in an MPEG file. Thus, each MPEG file will be
treated as an independent time code base. When two MPEG files
are connected together, the editor will make sure to generate a
new continuous PTS time code and preserve all PTS jumps within
the original 2 MPEG inputs. |