# Determine the Original Presentation Format in C++ > Read the original format of a loaded presentation in C++ with Aspose.Slides for C++, compare detection APIs, and handle files, streams, and legacy formats. Source: https://docs.aspose.com/slides/cpp/detect-presentation-source-format/ Updated: 2026-09-22 ## **Overview** After loading a presentation, call [Presentation::get_SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/presentation/get_sourceformat/) to determine its original format. The method is also available through [IPresentation::get_SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/ipresentation/get_sourceformat/). Use it when subsequent processing depends on the format from which the current instance was loaded. The source format is distinct from the [SaveFormat](https://reference.aspose.com/slides/cpp/aspose.slides.export/saveformat/) selected for an output file. Saving to another format does not change the source format of the existing instance. ## **Read the Source Format of a File** This example requires an existing `sample.pptx` file. It loads the file and selects an application processing policy using [Presentation::get_SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/presentation/get_sourceformat/), rather than the filename. Change the input path to try other formats. The example prints the selected policy; replace the messages with your application logic. ```cpp #include #include #include #include #include using namespace Aspose::Slides; using namespace System; auto presentation = MakeObject(u"sample.pptx"); switch (presentation->get_SourceFormat()) { case SourceFormat::Ppt: case SourceFormat::Pps: case SourceFormat::Pot: Console::WriteLine(u"Use the legacy PowerPoint processing policy."); break; case SourceFormat::Pptx: Console::WriteLine(u"Use the standard PPTX processing policy."); break; default: Console::WriteLine(String::Format(u"Use the general policy for {0}.", ObjectExt::ToString(presentation->get_SourceFormat()))); break; } ``` ## **Recognize the Supported Values** The [SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/sourceformat/) enumeration distinguishes the following presentation formats. The extensions below are conventional extensions, not a reconstruction of the original filename. | SourceFormat value | Extension | Format | | --- | --- | --- | | `Ppt` | `.ppt` | PowerPoint 97–2003 presentation | | `Pptx` | `.pptx` | Office Open XML presentation | | `Pptm` | `.pptm` | Macro-enabled Office Open XML presentation | | `Pps` | `.pps` | PowerPoint 97–2003 slide show | | `Ppsx` | `.ppsx` | Office Open XML slide show | | `Ppsm` | `.ppsm` | Macro-enabled Office Open XML slide show | | `Pot` | `.pot` | PowerPoint 97–2003 template | | `Potx` | `.potx` | Office Open XML template | | `Potm` | `.potm` | Macro-enabled Office Open XML template | | `Odp` | `.odp` | OpenDocument presentation | | `Otp` | `.otp` | OpenDocument presentation template | | `Fodp` | `.fodp` | Flat XML ODF presentation | | `Xml` | `.xml` | PowerPoint XML presentation | ## **Read the Source Format of a Stream** This example requires an existing `sample.pps` file. Reading its bytes into a memory stream models input received without a filename, such as a database value or an uploaded byte array. The [Presentation](https://reference.aspose.com/slides/cpp/aspose.slides/presentation/) constructor receives only the stream. ```cpp #include #include #include #include #include #include #include using namespace Aspose::Slides; using namespace System; using namespace System::IO; auto bytes = File::ReadAllBytes(u"sample.pps"); auto stream = MakeObject(bytes); auto presentation = MakeObject(stream); Console::WriteLine(String::Format(u"Source format: {0}", ObjectExt::ToString(presentation->get_SourceFormat()))); ``` PPT, PPS, and POT use the same underlying binary format. When loading by file path, the extension can help distinguish a slide show or template. Without a filename, legacy PPS and POT content may be reported as `SourceFormat::Ppt`; the PPS example above reports `Ppt`. If your application must preserve the distinction, keep the original filename or subtype metadata separately. An extension is a useful hint for these legacy subtypes, but should not be the only basis for identifying arbitrary presentation content. ## **Compare Detection Before and After Loading** Use [PresentationFactory::GetPresentationInfo](https://reference.aspose.com/slides/cpp/aspose.slides/presentationfactory/getpresentationinfo/) and [IPresentationInfo::get_LoadFormat](https://reference.aspose.com/slides/cpp/aspose.slides/ipresentationinfo/get_loadformat/) when you need to inspect a file before loading its complete presentation object model. Use [Presentation::get_SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/presentation/get_sourceformat/) when the instance already exists. This example requires `sample.pptx` and prints `Pptx` for both checks. In production, choose the API appropriate to your processing stage; an already loaded presentation does not need a second inspection solely to obtain its source format. ```cpp #include #include #include #include #include #include #include #include using namespace Aspose::Slides; using namespace System; auto path = String(u"sample.pptx"); auto information = PresentationFactory::get_Instance()->GetPresentationInfo(path); Console::WriteLine(String::Format(u"Before loading: {0}", ObjectExt::ToString(information->get_LoadFormat()))); auto presentation = MakeObject(path); Console::WriteLine(String::Format(u"After loading: {0}", ObjectExt::ToString(presentation->get_SourceFormat()))); ``` The results have different enumeration types: [LoadFormat](https://reference.aspose.com/slides/cpp/aspose.slides/loadformat/) and [SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/sourceformat/). Do not compare them by casting their numeric values or assume that every format has identical detection results. PowerPoint XML can be reported as `LoadFormat::Unknown` before loading and `SourceFormat::Xml` after loading. ## **Keep Source and Output Formats Separate** This example requires `sample.pptx` and writes `converted.odp`. It prints `Pptx` both before and after saving the original instance. Only the new instance loaded from the ODP output reports `Odp`. ```cpp #include #include #include #include #include #include using namespace Aspose::Slides; using namespace System; using namespace Aspose::Slides::Export; auto presentation = MakeObject(u"sample.pptx"); Console::WriteLine(String::Format(u"Before saving: {0}", ObjectExt::ToString(presentation->get_SourceFormat()))); presentation->Save(u"converted.odp", SaveFormat::Odp); Console::WriteLine(String::Format(u"After saving: {0}", ObjectExt::ToString(presentation->get_SourceFormat()))); auto reopened = MakeObject(u"converted.odp"); Console::WriteLine(String::Format(u"Reopened output: {0}", ObjectExt::ToString(reopened->get_SourceFormat()))); ``` A presentation created from scratch with `MakeObject()` reports `SourceFormat::Pptx`. It has no input file: this is the default value for a newly created instance, not evidence that a PPTX file was loaded. Track whether your application created or loaded the instance separately if that distinction matters. ## **Map a Source Format to an Extension** The following example requires `sample.pptx`. It maps every currently supported [SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/sourceformat/) value to a conventional extension, without parsing the input filename. The fallback avoids silently assigning an extension to an unrecognized value. ```cpp #include #include #include #include #include using namespace Aspose::Slides; using namespace System; auto presentation = MakeObject(u"sample.pptx"); auto extension = String::Empty; switch (presentation->get_SourceFormat()) { case SourceFormat::Ppt: extension = u".ppt"; break; case SourceFormat::Pptx: extension = u".pptx"; break; case SourceFormat::Pptm: extension = u".pptm"; break; case SourceFormat::Pps: extension = u".pps"; break; case SourceFormat::Ppsx: extension = u".ppsx"; break; case SourceFormat::Ppsm: extension = u".ppsm"; break; case SourceFormat::Pot: extension = u".pot"; break; case SourceFormat::Potx: extension = u".potx"; break; case SourceFormat::Potm: extension = u".potm"; break; case SourceFormat::Odp: extension = u".odp"; break; case SourceFormat::Otp: extension = u".otp"; break; case SourceFormat::Fodp: extension = u".fodp"; break; case SourceFormat::Xml: extension = u".xml"; break; default: break; } Console::WriteLine(extension.IsEmpty() ? u"No extension mapping is available." : extension); ``` This mapping does not convert a file or recover a legacy PPS/POT subtype lost during stream loading. For actual saving, select a [SaveFormat](https://reference.aspose.com/slides/cpp/aspose.slides.export/saveformat/) explicitly, or use the conversion shown in [Save Presentations in Their Original Format](/slides/cpp/save-presentation/#save-presentations-in-their-original-format). ## **Verify Formats by Saving and Reopening** This self-contained example creates a presentation and writes three files in the working directory, overwriting files with the same names. It reopens each output both by path and through a memory stream. For PPTX and ODP, both routes report the saved format. For PPS, loading by path reports `Pps`, while loading the same bytes without a filename reports `Ppt`. ```cpp #include #include #include #include #include #include #include #include #include using namespace Aspose::Slides; using namespace System; using namespace Aspose::Slides::Export; using namespace System::IO; auto presentation = MakeObject(); auto formats = MakeArray({SaveFormat::Pptx, SaveFormat::Odp, SaveFormat::Pps}); for (auto format : formats) { auto formatName = ObjectExt::ToString(format); auto path = String::Format(u"roundtrip.{0}", formatName.ToLowerInvariant()); presentation->Save(path, format); auto fromFile = MakeObject(path); auto bytes = File::ReadAllBytes(path); auto stream = MakeObject(bytes); auto fromStream = MakeObject(stream); Console::WriteLine(String::Format(u"{0}: file={1}, stream={2}", formatName, ObjectExt::ToString(fromFile->get_SourceFormat()), ObjectExt::ToString(fromStream->get_SourceFormat()))); } ``` The following table summarizes source-format identification for presentations with matching extensions: | Saved format | SourceFormat from a file path | SourceFormat from a nameless stream | | --- | --- | --- | | PPT | `Ppt` | `Ppt` | | PPTX, PPTM | `Pptx`, `Pptm` respectively | Same as file path | | PPS | `Pps` | `Ppt` | | PPSX, PPSM | `Ppsx`, `Ppsm` respectively | Same as file path | | POT | `Pot` | `Ppt` | | POTX, POTM | `Potx`, `Potm` respectively | Same as file path | | ODP, OTP | `Odp`, `Otp` respectively | Same as file path | | FODP | `Fodp` | `Fodp` | | PowerPoint XML | `Xml` | `Xml` | Legacy PPS/POT content is normalized to `Ppt` for nameless streams. The table describes format identification, not preservation of every presentation feature during conversion. ## **FAQ** **Does saving to ODP change the source format of a presentation loaded from PPTX?** No. The existing instance still reports `Pptx`. An instance loaded from the saved ODP file reports `Odp`. **Can a stream always distinguish a legacy presentation, slide show, and template?** No. PPT, PPS, and POT share the binary format. Keep filename or subtype metadata separately when that distinction is required. **Which API should I use if the presentation is already loaded?** Read [Presentation::get_SourceFormat](https://reference.aspose.com/slides/cpp/aspose.slides/presentation/get_sourceformat/). Use [PresentationFactory::GetPresentationInfo](https://reference.aspose.com/slides/cpp/aspose.slides/presentationfactory/getpresentationinfo/) for inspection before loading.