[FFmpeg-trac] #4804(undetermined:new): "Buffer queue overflow, dropping." when splitting input into thumbnail and overlay filters.
FFmpeg
trac at avcodec.org
Mon Dec 5 16:28:46 EET 2016
#4804: "Buffer queue overflow, dropping." when splitting input into thumbnail and
overlay filters.
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Reporter: starfires | Owner:
Type: defect | Status: new
Priority: important | Component:
Version: git-master | undetermined
Keywords: regression | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Comment (by Misaki):
The root cause might be that the thumbnail filter is somehow marking the
frames as unavailable to 'pass on' to a later filter (or in this case to
be output to the encoder), even though the stream has supposedly been
split. I have encountered a bug like this that I hopefully documented
somewhere but would have to confirm whether it still exists, where some
type of action on one output of a split filter was affecting the other
outputs. Maybe trying to change the range from mpeg to pc/jpeg with a
scale filter without actually modifying the pixels in any other way
(probably so a lut filter could use that expanded range).
As a workaround, someone in this very specific situation could try just
using separate filtergraphs, with a movie filter to add the png. '-vf
movie=[..],[in]overlay' before the mp4 output, and '-vf thumbnail' before
the jpeg output. If this works, it suggests the cause is indeed in how the
filtergraph and specifically the split filter works, and not because there
is an actual conflict between the thumbnail graph's memory requirements
and the limited (~64?) number of frames that the overlay filter will
buffer.
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Ticket URL: <https://trac.ffmpeg.org/ticket/4804#comment:7>
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