In the encoding result, the offset of iloc is 0 but the display effect is not affected. Why?

strukturag / libheif

libheif is an HEIF and AVIF file format decoder and encoder.

Other

1.77k stars 306 forks source link

In the encoding result, the offset of iloc is 0 but the display effect is not affected. Why? #1368

Closed yqbgq closed 3 weeks ago

yqbgq commented 3 weeks ago

I would like to ask why the offset in the iloc of my encoding result is 0, which does not affect the display result.

Thanks!

farindk commented 3 weeks ago

Please attach the file.

bradh commented 3 weeks ago

As @farindk says, we would need to see the file, but there are at least two possibilities - the dumping is wrong, or there is a base_offset value that is not shown.

yqbgq commented 3 weeks ago

Sorry, the cause of the problem is that I do not understand the heif format. In the heif file obtained from a third party, base_offset is incorrectly set to 0 and extend_offset is set to writer_pos. Therefore, offset is not displayed as 0 during software parsing.

Thanks to farindk and bradh for their help.