Changes between Initial Version and Version 1 of Ticket #4804, comment 7


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Timestamp:
Dec 5, 2016, 4:29:49 PM (2 years ago)
Author:
Misaki
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  • Ticket #4804, comment 7

    initial v1  
    11The 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).
    22
    3 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.
     3As 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.