AccessViolationException calling avio_close

[ispysoftware]

Just updated to the latest version and using the latest build from ffmpeg and my code is throwing AccessViolationException wherever i'm calling avio_close. Are you seeing the same thing?
Not sure if this is a problem with ffmpeg or the wrapper

[Ruslan-B]

I don't see any difference in bindings for avio_close. The main difference between 5.0 and 5.1 is in macros part.
Can you create a minimal test?

[ispysoftware]

thanks for getting back to me.

I found the issue, setting formatContext->pb->seekable = 1 breaks it now for some reason

           var outputFormat = av_guess_format("mp4", @"D:\test.mp4", null);
            var formatContext = avformat_alloc_context();
            formatContext->oformat = outputFormat;
            var videoStream = avformat_new_stream(formatContext, null);
            var videoCodec = avcodec_find_encoder(AVCodecID.AV_CODEC_ID_H264);
            var videoCodecContext = avcodec_alloc_context3(videoCodec);
            avcodec_open2(videoCodecContext, videoCodec, null);
            avio_open(&formatContext->pb, @"D:\test.mp4", AVIO_FLAG_WRITE);
            formatContext->pb->seekable = 1; //<-- comment out to fix
            avformat_write_header(formatContext, null);
            avio_close(formatContext->pb);  //<-- oopsie

[ispysoftware]

i logged a ticket with ffmpeg and they said it's working fine on their side so possibly some issue with the wrapper?

https://trac.ffmpeg.org/ticket/9871?cversion=1&cnum_hist=2

[Ruslan-B]

I see meanwhile can you try new packages #210 (comment)?

DynamicallyLoaded is the closest to what we have now.
StaticallyLinked - is mostly for iOS as ffmpeg is linked statically.
DynamicallyLinked - is a DllImport import version.

In the very beginning you have to initialize the API then the rest is similar to what you have already:
DynamicallyLoadedBindings.Initialize();

[Ruslan-B]

I'll test sniped you wrote.

[ispysoftware]

i can't test that update unfortunately as my project is .net standard 2.0 and i can't update that to 2.1 as that breaks compat with the 4.8 framework project that uses it.

Is there a reason you're using the 2.1 version of net standard? It limits the usability of the library quite a lot.

[Ruslan-B]

Well UnmanagedType.LPUTF8Str is in only in 2.1 standard - and this going to be newest version which supposed to support only net 6.0 as the rest is unsupported by MS any more. Custom marshaller - UTF8Marshaler can help here however in general I would prefer to drop anything lower than 2.1 standard.

[ispysoftware]

the full .net framework is still supported by MS

Support lifecycle
.NET Framework 4.8 is the latest version of .NET Framework and will continue to be distributed with future releases of Windows. As long as it is installed on a supported version of Windows, .NET Framework 4.8 will continue to also be supported.

https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-framework

[Ruslan-B]

Okay I'll add it to targets then.

[ispysoftware]

Hey @Ruslan-B did you manage to repro the original issue?

[Ruslan-B]

Confirming same exception while using .NET 6.0.400 and GPL FFmpeg 5.1.
Using new or old bindings.
Update:
It works for .NET 6.0.400 and GPL FFmpeg 4.4

Here is the log from 5.1

FFmpeg version info: 5.1-full_build-www.gyan.dev
[libx264 @ 00000148f57217c0] The encoder timebase is not set.
[file @ 00000148f5721bc0] Setting default whitelist 'file,crypto,data'
[mp4 @ 00000148f5720c80] Could not find tag for codec none in stream #0, codec not currently supported in container
[AVIOContext @ 00000148f5761dc0] Statistics: 0 bytes written, 0 seeks, 0 writeouts
Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at FFmpeg.AutoGen.Bindings.DynamicallyLoaded.DynamicallyLoadedBindings+<>c.<Initialize>b__6_583(FFmpeg.AutoGen.Abstractions.AVIOContext*)
   at FFmpeg.AutoGen.Abstractions.ffmpeg.avio_close(FFmpeg.AutoGen.Abstractions.AVIOContext*)
   at FFmpeg.AutoGen.Example.Program.Main(System.String[])

And working 4.4

FFmpeg version info: 4.4-full_build-www.gyan.dev
[libx264 @ 000001cdf5124200] The encoder timebase is not set.
[mp4 @ 000001cdf5122d00] Could not find tag for codec none in stream #0, codec not currently supported in container

It doesn't seems like bindings or marshaling - something different.

[hglee]

Hi,

I found different size of checksum in AVIOContext. So it has different offset after checksum.

FFmpeg.AutoGen/FFmpeg/include/libavformat/avio.h

Line 246 in 5194d11

unsigned long checksum;

FFmpeg.AutoGen/FFmpeg.AutoGen/FFmpeg.structs.g.cs

Line 2060 in d7f6e23

public ulong @checksum;