Opened 6 months ago

Last modified 6 months ago

#6286 new defect

apng doesn't play correct

Reported by: hxuanyu Owned by:
Priority: normal Component: avcodec
Version: git-master Keywords: png
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no

Description

This issue is reproducible on latest ffplay build

ffplay.exe png1.apng
ffplay version N-85091-g23ae3cc Copyright (c) 2003-2017 the FFmpeg developers

This apng file includes 3 frames:

  1. 1st a 100x100 white frame, dispose_op = 1
  2. 2nd a 50x50 red frame, dispose_op = 1
  3. 3rd a 50x50 blue frame, dispose_op = 1

while played in ffplay, when 2nd and 3rd frames are played, background is black.

But when played in Mozilla Firefox or disassembled by APNG Disassembler2.8, 2nd and 3rd frames have white background!

Attachments (1)

png1.apng (624 bytes) - added by hxuanyu 6 months ago.

Download all attachments as: .zip

Change History (3)

Changed 6 months ago by hxuanyu

comment:1 follow-up: Changed 6 months ago by cehoyos

  • Component changed from undetermined to avcodec
  • Keywords png added
  • Version changed from unspecified to git-master

How is this issue related to FFplay?

comment:2 in reply to: ↑ 1 Changed 6 months ago by hxuanyu

Thanks cehoyos,

I'll be more precise next time.

As for this bug, actually I'm a bit confused. The spec says dispose_op = 1 means the frame's region of the output buffer is to be cleared to fully transparent black before rendering the next frame.

So before 2nd frame is shown, 1st frame buffer 100x100 area should be cleared. So actually current ffmpeg behavior is correct?

Replying to cehoyos:

How is this issue related to FFplay?

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