Packaging fails if input content contains SampleGroupDescriptionBox with 0 entries

[ghost]

Operating System: <e.g. kALI LINUX 2019.4>
Shaka Packager Version: <e.g. v2.4.3>
I used the "built from source" method to build the packager on my kali machine. No errors. It seemed like it will work fine.

Issue and steps to reproduce the problem

Then i run this simple command to test
./packager in=/root/video.mp4 --dump_stream_info
Packager Command:
./packager in=/root/video.mp4 --dump_stream_info
Extra steps to reproduce the problem?
(1)Just follow the third method which is "built from source" and build the packager.
(2)then just run a simple command and it is not working

What is the expected result?
It should dump the stream_info for the media file.
What happens instead?
It rather shows this error

[0806/022106:INFO:demuxer.cc(88)] Demuxer::Run() on file 'video.mp4'.
[0806/022106:INFO:demuxer.cc(160)] Initialize Demuxer for file 'video.mp4'.
[0806/022107:ERROR:box_definitions.cc(1062)] Failure while processing: count != 0
[0806/022107:ERROR:box_reader.h(146)] Failure while processing: child_itr->Parse(itr->second.get())
[0806/022107:ERROR:box_definitions.cc(1185)] Failure while processing: buffer->reader()->TryReadChildren(&sample_group_descriptions) && buffer->reader()->TryReadChildren(&sample_to_groups)
[0806/022107:ERROR:box_reader.cc(97)] Failure while processing: child->Parse(itr->second.get())
[0806/022107:ERROR:box_definitions.cc(2167)] Failure while processing: ReadWriteHeaderInternal(buffer) && buffer->PrepareChildren() && buffer->ReadWriteChild(&dinf) && buffer->ReadWriteChild(&sample_table)
[0806/022107:ERROR:box_reader.cc(97)] Failure while processing: child->Parse(itr->second.get())
[0806/022107:ERROR:box_definitions.cc(2230)] Failure while processing: buffer->ReadWriteChild(&information)
[0806/022107:ERROR:box_reader.cc(97)] Failure while processing: child->Parse(itr->second.get())
[0806/022107:ERROR:box_definitions.cc(2252)] Failure while processing: ReadWriteHeaderInternal(buffer) && buffer->PrepareChildren() && buffer->ReadWriteChild(&header) && buffer->ReadWriteChild(&media) && buffer->TryReadWriteChild(&edit) && buffer->TryReadWriteChild(&sample_encryption)
[0806/022107:ERROR:box_reader.h(146)] Failure while processing: child_itr->Parse(itr->second.get())
[0806/022107:ERROR:box_reader.h(129)] Failure while processing: TryReadChildren(children) && !children->empty()
[0806/022107:ERROR:box_definitions.cc(2351)] Failure while processing: reader->ReadChildren(&tracks) && reader->TryReadChild(&extends) && reader->TryReadChildren(&pssh)
[0806/022107:ERROR:mp4_media_parser.cc(377)] Failure while processing: moov_->Parse(reader)
[0806/022107:ERROR:packager_main.cc(552)] Packaging Error: 8 (PARSER_FAILURE): Cannot parse media file video.mp4

<Please attach the input files or email to shaka-packager-issues@google.com.>

[kqyang]

@Akata01 Thanks for the bug report.

The code fails at https://github.com/google/shaka-packager/blob/540c0aaffbb2c55e156991f6c1717da44ace5ba1/packager/media/formats/mp4/box_definitions.cc#L1062.

A SampleGroupDescriptionBox (sgpd) with 0 number of entries is meaningless, but we shouldn't error out.

A possible fix is to change the code to:

if (buffer->Reading()) {
  if (count == 0)
    return true;
} else {
  RCHECK(count != 0);
}

Are you interested in sending a PR to us to fix it?

[ghost]

@kqyang i made the changes you suggested in box_defentions.cc and rebulit it and it worked.
Yes i am interested in making the PR.
Here is the result

[kqyang]

Cool. Thanks. Looking forward to your PR!