From 1a49d0a81231981b7a2f3e3d11212cbdcd03652d Mon Sep 17 00:00:00 2001
From: James Crook <james.k.crook@gmail.com>
Date: Sun, 1 Sep 2019 12:41:24 +0100
Subject: [PATCH] Bug 59 - Residual.  MP2 exporting is broken.  So disable it.

This fix also allows for reporting illegal combinations on OK.  However, we don't yet need to use that feature, as the dialog now prevents illegal combinations EVEN when you use 'Show all Codecs'
---
 src/export/ExportFFmpegDialogs.cpp | 70 ++++++++++++++++++++++++++++++
 src/export/ExportFFmpegDialogs.h   |  3 ++
 2 files changed, 73 insertions(+)

diff --git a/src/export/ExportFFmpegDialogs.cpp b/src/export/ExportFFmpegDialogs.cpp
index 077d7b05b..5b5e9e38f 100644
--- a/src/export/ExportFFmpegDialogs.cpp
+++ b/src/export/ExportFFmpegDialogs.cpp
@@ -1457,6 +1457,9 @@ void ExportFFmpegOptions::FetchCodecList()
       // We're only interested in audio and only in encoders
       if (codec->type == AVMEDIA_TYPE_AUDIO && av_codec_is_encoder(codec))
       {
+         // MP2 Codec is broken.  Don't allow it.
+         if( codec->id == AV_CODEC_ID_MP2)
+            continue;
          mCodecNames.push_back(wxString::FromUTF8(codec->name));
          mCodecLongNames.push_back(wxString::Format(wxT("%s - %s"),mCodecNames.back(),wxString::FromUTF8(codec->long_name)));
       }
@@ -1719,6 +1722,9 @@ int ExportFFmpegOptions::FetchCompatibleCodecList(const wxChar *fmt, AVCodecID i
       {
          if (codec->type == AVMEDIA_TYPE_AUDIO && av_codec_is_encoder(codec))
          {
+            // MP2 is broken.
+            if( codec->id == AV_CODEC_ID_MP2)
+               continue;
             if (! make_iterator_range( mShownCodecNames )
                .contains( wxString::FromUTF8(codec->name) ) )
             {
@@ -1969,6 +1975,67 @@ void ExportFFmpegOptions::OnAllCodecs(wxCommandEvent& WXUNUSED(event))
    mCodecList->Append(mCodecNames);
 }
 
+/// ReportIfBadCombination will trap 
+/// bad combinations of format and codec and report
+/// using a message box.
+/// We may later extend it to catch bad parameters too.
+/// @return true iff a bad combination was reported
+/// At the moment we don't trap unrecognised format
+/// or codec.  (We do not expect them to happen ever).
+bool ExportFFmpegOptions::ReportIfBadCombination()
+{
+   wxString *selcdc = NULL;
+   wxString *selcdclong = NULL;
+   FindSelectedCodec(&selcdc, &selcdclong);
+   if (selcdc == NULL)
+      return false; // unrecognised codec. Treated as OK
+   AVCodec *cdc = avcodec_find_encoder_by_name(selcdc->ToUTF8());
+   if (cdc == NULL)
+      return false; // unrecognised codec. Treated as OK
+
+   wxString *selfmt = NULL;
+   wxString *selfmtlong = NULL;
+   FindSelectedFormat(&selfmt, &selfmtlong);
+   if( selfmt == NULL )
+      return false; // unrecognised format; Treated as OK
+   
+   // This is intended to test for illegal combinations.
+   // However, the list updating now seems to be working correctly
+   // making it impossible to select illegal combinations
+   bool bFound = false;
+   for (int i = 0; CompatibilityList[i].fmt != NULL; i++)
+   {
+      if (*selfmt == CompatibilityList[i].fmt) 
+      {
+         if (CompatibilityList[i].codec == cdc->id || (CompatibilityList[i].codec == AV_CODEC_ID_NONE) ){
+            bFound = true;
+            break;
+         }
+      }
+   }
+
+   // We can put extra code in here, to disallow combinations
+   // We could also test for illegal parameters, and deliver
+   // custom error messages in that case.
+   // The below would make AAC codec disallowed.
+   //if( cdc->id == AV_CODEC_ID_AAC)
+   //   bFound = false;
+
+   // Valid combination was found, so no reporting.
+   if( bFound )
+      return false;
+
+   AudacityMessageBox( 
+      wxString::Format(_("Format %s is not compatible with codec %s."),
+         *selfmt,
+         *selcdc ),
+      _("Incompatible format and codec"));
+
+   return true;
+}
+
+
+
 void ExportFFmpegOptions::EnableDisableControls(AVCodec *cdc, wxString *selfmt)
 {
    int handled = -1;
@@ -2098,6 +2165,9 @@ void ExportFFmpegOptions::OnCodecList(wxCommandEvent& WXUNUSED(event))
 ///
 void ExportFFmpegOptions::OnOK(wxCommandEvent& WXUNUSED(event))
 {
+   if( ReportIfBadCombination() )
+      return;
+
    int selcdc = mCodecList->GetSelection();
    int selfmt = mFormatList->GetSelection();
    if (selcdc > -1) gPrefs->Write(wxT("/FileFormats/FFmpegCodec"),mCodecList->GetString(selcdc));
diff --git a/src/export/ExportFFmpegDialogs.h b/src/export/ExportFFmpegDialogs.h
index 78ba55f2f..facf03b76 100644
--- a/src/export/ExportFFmpegDialogs.h
+++ b/src/export/ExportFFmpegDialogs.h
@@ -305,6 +305,9 @@ private:
    /// Retreives list of presets from configuration file
    void FetchPresetList();
 
+   bool ReportIfBadCombination();
+
+
    // Enables/disables controls based on format/codec combination,
    // leaving only relevant controls enabled.
    // Hiding the controls may have been a better idea,