diff --git a/dcmdata/apps/dcmcrle.cc b/dcmdata/apps/dcmcrle.cc
index 0a58a100d8..c81fc3402d 100644
--- a/dcmdata/apps/dcmcrle.cc
+++ b/dcmdata/apps/dcmcrle.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 2002-2022, OFFIS e.V.
+ *  Copyright (C) 2002-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -267,7 +267,7 @@ int main(int argc, char *argv[])
     }
 
     DcmXfer original_xfer(dataset->getOriginalXfer());
-    if (original_xfer.isEncapsulated())
+    if (original_xfer.isPixelDataCompressed())
     {
       OFLOG_INFO(dcmcrleLogger, "DICOM file is already compressed, converting to uncompressed transfer syntax first");
       if (EC_Normal != dataset->chooseRepresentation(EXS_LittleEndianExplicit, NULL))
diff --git a/dcmdata/apps/dump2dcm.cc b/dcmdata/apps/dump2dcm.cc
index 9cdc3e7118..f09fa159f3 100644
--- a/dcmdata/apps/dump2dcm.cc
+++ b/dcmdata/apps/dump2dcm.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 1994-2023, OFFIS e.V.
+ *  Copyright (C) 1994-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -1067,7 +1067,7 @@ int main(int argc, char *argv[])
         if (fileformat.canWriteXfer(opt_xfer))
         {
             /* check whether pixel data is compressed */
-            if ((opt_writeMode == EWM_dataset) && DcmXfer(xfer).isEncapsulated())
+            if ((opt_writeMode == EWM_dataset) && DcmXfer(xfer).usesEncapsulatedFormat())
             {
                 OFLOG_WARN(dump2dcmLogger, "encapsulated pixel data require file format, ignoring --write-dataset");
                 opt_writeMode = EWM_fileformat;
diff --git a/dcmdata/apps/mdfdsman.cc b/dcmdata/apps/mdfdsman.cc
index c89891f218..26d288f634 100644
--- a/dcmdata/apps/mdfdsman.cc
+++ b/dcmdata/apps/mdfdsman.cc
@@ -603,8 +603,8 @@ OFCondition MdfDatasetManager::saveFile(const char* file_name,
     /* check whether transfer syntax is possible */
     if ((opt_xfer == EXS_Unknown) || (dfile->canWriteXfer(opt_xfer)))
     {
-        /* check whether pixel data is compressed */
-        if (opt_dataset && DcmXfer(opt_xfer).isEncapsulated())
+        /* check whether pixel data is encapsulated (e.g. compressed) */
+        if (opt_dataset && DcmXfer(opt_xfer).usesEncapsulatedFormat())
         {
             OFLOG_WARN(mdfdsmanLogger, "encapsulated pixel data requires file format, ignoring --write-dataset");
             opt_dataset = OFFalse;
@@ -714,7 +714,7 @@ OFCondition MdfDatasetManager::checkPixelDataInsertion(DcmElement* elem)
             const DcmRepresentationParameter* dontCare = NULL;
             pix->getCurrentRepresentationKey(ts, dontCare);
             DcmXfer xfer(ts);
-            if (xfer.isEncapsulated())
+            if (xfer.usesEncapsulatedFormat())
             {
                 OFLOG_ERROR(mdfdsmanLogger, "Cannot replace encapsulated Pixel Data (not implemented)");
                 return EC_IllegalParameter;
diff --git a/dcmdata/apps/xml2dcm.cc b/dcmdata/apps/xml2dcm.cc
index c7529523db..4276cabcf2 100644
--- a/dcmdata/apps/xml2dcm.cc
+++ b/dcmdata/apps/xml2dcm.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 2003-2022, OFFIS e.V.
+ *  Copyright (C) 2003-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -350,7 +350,7 @@ int main(int argc, char *argv[])
             if (fileformat.canWriteXfer(opt_xfer))
             {
                 /* check whether pixel data is compressed */
-                if ((opt_writeMode == EWM_dataset) && DcmXfer(xfer).isEncapsulated())
+                if ((opt_writeMode == EWM_dataset) && DcmXfer(xfer).usesEncapsulatedFormat())
                 {
                     OFLOG_WARN(xml2dcmLogger, "encapsulated pixel data require file format, ignoring --write-dataset");
                     opt_writeMode = EWM_fileformat;
diff --git a/dcmdata/libi2d/i2d.cc b/dcmdata/libi2d/i2d.cc
index c6eb7925f5..73897652fd 100644
--- a/dcmdata/libi2d/i2d.cc
+++ b/dcmdata/libi2d/i2d.cc
@@ -608,7 +608,7 @@ OFCondition Image2Dcm::readAndInsertPixelDataFirstFrame(
   if (m_frameLength > 0) compressionRatio = uncompressedSize / m_frameLength;
 
   DcmXfer transport(outputTS);
-  if (transport.isEncapsulated())
+  if (transport.usesEncapsulatedFormat())
   {
     m_offsetList.clear();
     insertEncapsulatedPixelDataFirstFrame(dset, pixData, m_frameLength, outputTS);
@@ -786,7 +786,7 @@ OFCondition Image2Dcm::readAndInsertPixelDataNextFrame(
     cond = makeOFCondition(OFM_dcmdata, 18, OF_error, "Image2Dcm: value of vertical PixelAspectRatio not equal for all frames of the multi-frame image");
     return cond;
   }
-  if ((!transport.isEncapsulated()) && (next_frameLength != m_frameLength))
+  if (transport.isPixelDataUncompressed() && (next_frameLength != m_frameLength))
   {
     // in the case of uncompressed images, all frames must have exactly the same size.
     // for compressed images, where we store the compressed bitstream as a pixel item, this does not matter.
@@ -804,7 +804,7 @@ OFCondition Image2Dcm::readAndInsertPixelDataNextFrame(
   // We will divide this by the number of frames later.
   m_compressionRatio += compressionRatio;
 
-  if (transport.isEncapsulated())
+  if (transport.usesEncapsulatedFormat())
   {
     cond = insertEncapsulatedPixelDataNextFrame(pixData, next_frameLength);
     delete[] pixData;
diff --git a/dcmdata/libsrc/dcdatset.cc b/dcmdata/libsrc/dcdatset.cc
index 0de01b45eb..b9c86f95bf 100644
--- a/dcmdata/libsrc/dcdatset.cc
+++ b/dcmdata/libsrc/dcdatset.cc
@@ -751,7 +751,7 @@ OFCondition DcmDataset::chooseRepresentation(const E_TransferSyntax repType,
     // check if we are attempting to compress but the image contains
     // floating point or double floating point pixel data, which our codecs don't support.
     if ((tagExists(DCM_FloatPixelData, OFTrue) || tagExists(DCM_DoubleFloatPixelData, OFTrue)) &&
-         (fromrep.isEncapsulated() || torep.isEncapsulated()))
+         (fromrep.isPixelDataCompressed() || torep.isPixelDataCompressed()))
     {
         DCMDATA_ERROR("DcmDataset: Unable to compress/decompress floating point pixel data, cannot change representation");
         l_error = EC_CannotChangeRepresentation;
@@ -791,11 +791,11 @@ OFCondition DcmDataset::chooseRepresentation(const E_TransferSyntax repType,
     // If there are no pixel data elements in the dataset, issue a warning
     if (! pixelDataEncountered)
     {
-      if (torep.isEncapsulated() && ! fromrep.isEncapsulated())
+      if (torep.isPixelDataCompressed() && fromrep.isPixelDataUncompressed())
       {
         DCMDATA_WARN("DcmDataset: No pixel data present, nothing to compress");
       }
-      if (! torep.isEncapsulated() && fromrep.isEncapsulated())
+      if (torep.isPixelDataUncompressed() && fromrep.isPixelDataCompressed())
       {
         DCMDATA_WARN("DcmDataset: No pixel data present, nothing to decompress");
       }
@@ -886,7 +886,7 @@ OFCondition DcmDataset::doPostReadChecks()
   if (findAndGetElement(DCM_PixelData, pixData).good())
   {
       Uint32 valueLength = pixData->getLengthField();
-      if (xf.isEncapsulated())
+      if (xf.usesEncapsulatedFormat())
       {
           if (valueLength != DCM_UndefinedLength)
           {
@@ -897,8 +897,8 @@ OFCondition DcmDataset::doPostReadChecks()
                   /* encapsulated pixel data (always encoded with undefined */
                   /* length). Print and return an error. */
                   DCMDATA_ERROR("Found explicit length Pixel Data in top level "
-                  << "dataset with transfer syntax " << xf.getXferName()
-                  << ": Only undefined length permitted");
+                      << "dataset with transfer syntax " << xf.getXferName()
+                      << ": Only undefined length permitted");
                   result = EC_PixelDataExplLengthIllegal;
               }
               else
@@ -907,8 +907,8 @@ OFCondition DcmDataset::doPostReadChecks()
                   /* and behave like as we have the same case as for an */
                   /* icon image, which is always uncompressed (see above). */
                   DCMDATA_WARN("Found explicit length Pixel Data in top level "
-                  << "dataset with transfer syntax " << xf.getXferName()
-                  << ": Only undefined length permitted (ignored on explicit request)");
+                      << "dataset with transfer syntax " << xf.getXferName()
+                      << ": Only undefined length permitted (ignored on explicit request)");
               }
           }
       }
diff --git a/dcmdata/libsrc/dcpixel.cc b/dcmdata/libsrc/dcpixel.cc
index b5c682fb68..50451d60ba 100644
--- a/dcmdata/libsrc/dcpixel.cc
+++ b/dcmdata/libsrc/dcpixel.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 1997-2023, OFFIS e.V.
+ *  Copyright (C) 1997-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -186,7 +186,7 @@ DcmPixelData::calcElementLength(
     errorFlag = EC_Normal;
     Uint32 elementLength = 0;
 
-    if (xferSyn.isEncapsulated() && (! writeUnencapsulated(xfer)))
+    if (xferSyn.usesEncapsulatedFormat() && (! writeUnencapsulated(xfer)))
     {
         DcmRepresentationListIterator found;
         errorFlag = findConformingEncapsulatedRepresentation(xfer, NULL, found);
@@ -194,7 +194,7 @@ DcmPixelData::calcElementLength(
             elementLength = (*found)->pixSeq->calcElementLength(xfer, enctype);
     }
     else if (existUnencapsulated)
-        elementLength =  DcmPolymorphOBOW::calcElementLength(xfer, enctype);
+        elementLength = DcmPolymorphOBOW::calcElementLength(xfer, enctype);
     else
         errorFlag = EC_RepresentationNotFound;
 
@@ -216,9 +216,9 @@ DcmPixelData::canChooseRepresentation(
     // 1. we have uncompressed data, and target is uncompressed (conversion between uncompressed always possible)
     // 2. we have uncompressed and want compressed, but we are forced to write uncompressed anyway
     // 3. we want to go to compressed, and already have the desired representation available
-    if ((!toType.isEncapsulated() && existUnencapsulated) ||
-        (toType.isEncapsulated() && writeUnencapsulated(repType) && existUnencapsulated) ||
-        (toType.isEncapsulated() && findRepresentationEntry(findEntry, resultIt) == EC_Normal))
+    if ((toType.usesNativeFormat() && existUnencapsulated) ||
+        (toType.usesEncapsulatedFormat() && writeUnencapsulated(repType) && existUnencapsulated) ||
+        (toType.usesEncapsulatedFormat() && findRepresentationEntry(findEntry, resultIt) == EC_Normal))
     {
         // representation found
         result = OFTrue;
@@ -233,9 +233,9 @@ DcmPixelData::canChooseRepresentation(
           // we have uncompressed data, check whether we know how to go from uncompressed to desired compression
           result = DcmCodecList::canChangeCoding(EXS_LittleEndianExplicit, toType.getXfer());
         }
-        else if (toType.isEncapsulated())
+        else if (toType.usesEncapsulatedFormat())
         {
-          // we have already compressed data, check whether we know how to transcode
+          // we have encapsulated data, check whether we know how to transcode
           result = DcmCodecList::canChangeCoding((*original)->repType, toType.getXfer());
           if (!result)
           {
@@ -260,9 +260,9 @@ DcmPixelData::canWriteXfer(
 {
     DcmXfer newXferSyn(newXfer);
     DcmRepresentationListIterator found;
-    OFBool result = existUnencapsulated && (!newXferSyn.isEncapsulated() || writeUnencapsulated(newXfer));
+    OFBool result = existUnencapsulated && (newXferSyn.usesNativeFormat() || writeUnencapsulated(newXfer));
 
-    if (!result && newXferSyn.isEncapsulated())
+    if (!result && newXferSyn.usesEncapsulatedFormat())
         result = (findConformingEncapsulatedRepresentation(newXferSyn, NULL, found) == EC_Normal);
     return result;
 }
@@ -278,8 +278,8 @@ DcmPixelData::chooseRepresentation(
 
     const DcmRepresentationEntry findEntry(repType, repParam, NULL);
     DcmRepresentationListIterator result(repListEnd);
-    if ((!toType.isEncapsulated() && existUnencapsulated) ||
-        (toType.isEncapsulated() && findRepresentationEntry(findEntry, result) == EC_Normal))
+    if ((toType.usesNativeFormat() && existUnencapsulated) ||
+        (toType.usesEncapsulatedFormat() && findRepresentationEntry(findEntry, result) == EC_Normal))
     {
         // representation found
         current = result;
@@ -291,14 +291,14 @@ DcmPixelData::chooseRepresentation(
         if (original == repListEnd)
             l_error = encode(EXS_LittleEndianExplicit, NULL, NULL,
                              toType, repParam, pixelStack);
-        else if (toType.isEncapsulated())
+        else if (toType.usesEncapsulatedFormat())
             l_error = encode((*original)->repType, (*original)->repParam,
                              (*original)->pixSeq, toType, repParam, pixelStack);
         else
             l_error = decode((*original)->repType, (*original)->repParam,
                              (*original)->pixSeq, pixelStack);
     }
-    if (l_error.bad() && toType.isEncapsulated() && existUnencapsulated && writeUnencapsulated(repType))
+    if (l_error.bad() && toType.usesEncapsulatedFormat() && existUnencapsulated && writeUnencapsulated(repType))
         // Encoding failed so this will be written out unencapsulated
         l_error = EC_Normal;
     return l_error;
@@ -478,11 +478,11 @@ DcmPixelData::encode(
     DcmStack & pixelStack)
 {
     OFCondition l_error = EC_CannotChangeRepresentation;
-    if (toType.isEncapsulated())
+    if (toType.usesEncapsulatedFormat())
     {
        DcmPixelSequence * toPixSeq = NULL;
        OFBool removeOldPixelRepresentation = OFFalse;
-       if (fromType.isEncapsulated())
+       if (fromType.usesEncapsulatedFormat())
        {
          l_error = DcmCodecList::encode(fromType.getXfer(), fromParam, fromPixSeq,
                    toType.getXfer(), toParam, toPixSeq, pixelStack, removeOldPixelRepresentation);
@@ -513,7 +513,7 @@ DcmPixelData::encode(
 
        // if it was possible to convert one encapsulated syntax into
        // another directly try it using decoding and encoding!
-       if (l_error.bad() && fromType.isEncapsulated())
+       if (l_error.bad() && fromType.usesEncapsulatedFormat())
        {
            l_error = decode(fromType, fromParam, fromPixSeq, pixelStack);
            if (l_error.good()) l_error = encode(EXS_LittleEndianExplicit, NULL, NULL, toType, toParam, pixelStack);
@@ -559,7 +559,7 @@ DcmPixelData::findConformingEncapsulatedRepresentation(
     // of this pixel data element which meets both
     // the transfer syntax and (if given) the representation
     // parameter (i.e. quality factor for lossy JPEG).
-    if (repTypeSyn.isEncapsulated())
+    if (repTypeSyn.usesEncapsulatedFormat())
     {
         // first we check the current (active) representation if any.
         if ((current != repListEnd) && ((*current)->repType == repType) &&
@@ -617,9 +617,9 @@ DcmPixelData::hasRepresentation(
 {
     DcmXfer repTypeSyn(repType);
     DcmRepresentationListIterator found;
-    if (!repTypeSyn.isEncapsulated() && existUnencapsulated)
+    if (repTypeSyn.usesNativeFormat() && existUnencapsulated)
         return OFTrue;
-    else if (repTypeSyn.isEncapsulated())
+    else if (repTypeSyn.usesEncapsulatedFormat())
         return findConformingEncapsulatedRepresentation(repTypeSyn, repParam, found).good();
     return OFFalse;
 }
@@ -633,7 +633,7 @@ DcmPixelData::getLength(const E_TransferSyntax xfer,
     errorFlag = EC_Normal;
     Uint32 valueLength = 0;
 
-    if (xferSyn.isEncapsulated() && !writeUnencapsulated(xfer))
+    if (xferSyn.usesEncapsulatedFormat() && !writeUnencapsulated(xfer))
     {
         DcmRepresentationListIterator foundEntry;
         errorFlag = findConformingEncapsulatedRepresentation(
@@ -819,15 +819,14 @@ DcmPixelData::read(
         /* create a DcmXfer object based on the transfer syntax which was passed */
         DcmXfer ixferSyn(ixfer);
 
-        /* determine if the pixel data is captured in native (uncompressed) or encapsulated
-         * (compressed) format.  We only derive this information from the length field
-         * which is set to undefined length for encapsulated data because even in
-         * compressed transfer syntaxes the Icon Image Sequence may contain an
-         * uncompressed image.
+        /* determine if the pixel data is captured in native or encapsulated format.
+         * We only derive this information from the length field which is set to
+         * undefined length for encapsulated data because even in compressed transfer
+         * syntaxes the Icon Image Sequence may contain an uncompressed image.
          */
         if (getLengthField() == DCM_UndefinedLength)
         {
-            /* the pixel data is captured in encapsulated (compressed) format */
+            /* the pixel data is captured in encapsulated (e.g. compressed) format */
 
             /* if the transfer state is ERW_init, we need to prepare */
             /* the reading of the pixel data from the stream. */
@@ -841,14 +840,15 @@ DcmPixelData::read(
                 existUnencapsulated = OFFalse;
                 setTransferState(ERW_inWork);
 
-                if (! ixferSyn.isEncapsulated())
+                if (! ixferSyn.usesEncapsulatedFormat())
                 {
-                  /* Special case: we have encountered a compressed image
-                   * although we're decoding an uncompressed transfer syntax.
-                   * This could be a compressed image stored without meta-header.
-                   * For now, we just accept the data element; however, any attempt
-                   * to write the dataset will fail because no suitable decoder
-                   * is known.
+                  /* Special case: we have encountered encapsulated format for
+                   * the pixel data (undefined element length) although we're
+                   * decoding a non-encapsulated transfer syntax. This could e.g.
+                   * be a compressed image stored without meta-header. For now,
+                   * we just accept the data element; however, any attempt to
+                   * write the dataset will fail because no suitable decoder is
+                   * known.
                    */
                 }
             }
@@ -875,11 +875,11 @@ DcmPixelData::read(
                 recalcVR();
                 existUnencapsulated = OFTrue;
 
-                if (ixferSyn.isEncapsulated())
+                if (ixferSyn.usesEncapsulatedFormat())
                 {
-                  /* Special case: we have encountered an uncompressed image
-                   * although we're decoding an encapsulated transfer syntax.
-                   * This is probably an icon image.
+                  /* Special case: we have encountered native format for the pixel
+                   * data (explicit element length) although we're decoding an
+                   * encapsulated transfer syntax. This is probably an icon image.
                    */
                   alwaysUnencapsulated = OFTrue;
                 }
@@ -930,7 +930,8 @@ DcmPixelData::removeOriginalRepresentation(
     OFCondition l_error = EC_Normal;
     DcmXfer repTypeSyn(repType);
 
-    if (!repTypeSyn.isEncapsulated())
+    /* native format or referenced pixel data */
+    if (!repTypeSyn.usesEncapsulatedFormat())
     {
         if (original != repListEnd)
         {
@@ -947,6 +948,7 @@ DcmPixelData::removeOriginalRepresentation(
     }
     else
     {
+        /* encapsulated format */
         DcmRepresentationListIterator result;
         DcmRepresentationEntry findEntry(repType, repParam, NULL);
         if (findRepresentationEntry(findEntry, result) == EC_Normal)
@@ -984,7 +986,8 @@ DcmPixelData::removeRepresentation(
     OFCondition l_error = EC_Normal;
     DcmXfer repTypeSyn(repType);
 
-    if (!repTypeSyn.isEncapsulated())
+    /* native format or referenced pixel data */
+    if (!repTypeSyn.usesEncapsulatedFormat())
     {
         if (original != repListEnd && existUnencapsulated)
         {
@@ -996,6 +999,7 @@ DcmPixelData::removeRepresentation(
     }
     else
     {
+        /* encapsulated format */
         DcmRepresentationListIterator result;
         DcmRepresentationEntry findEntry(repType, repParam, NULL);
         if (findRepresentationEntry(findEntry, result) == EC_Normal)
@@ -1063,11 +1067,11 @@ OFCondition DcmPixelData::write(
   if (getTransferState() == ERW_notInitialized) errorFlag = EC_IllegalCall;
   else
   {
-    // check if the output transfer syntax is encapsulated
-    // and we are not requested to write an uncompressed dataset
+    // check if the output transfer syntax is encapsulated and
+    // we are not requested to write an uncompressed dataset,
     // for example because this is within an Icon Image Sequence
     DcmXfer xferSyn(oxfer);
-    if (xferSyn.isEncapsulated() && (! writeUnencapsulated(oxfer)))
+    if (xferSyn.usesEncapsulatedFormat() && (! writeUnencapsulated(oxfer)))
     {
       // write encapsulated representation (i.e., compressed image)
       if (getTransferState() == ERW_init)
@@ -1129,7 +1133,7 @@ OFCondition DcmPixelData::writeSignatureFormat(
   else if (getTag().isSignable())
   {
     DcmXfer xferSyn(oxfer);
-    if (xferSyn.isEncapsulated() && (! writeUnencapsulated(oxfer)))
+    if (xferSyn.usesEncapsulatedFormat() && (! writeUnencapsulated(oxfer)))
     {
       if (getTransferState() == ERW_init)
       {
@@ -1273,7 +1277,7 @@ OFBool DcmPixelData::writeUnencapsulated(const E_TransferSyntax xfer)
 
     if (alwaysUnencapsulated)
         return OFTrue;
-    if (DcmXfer(xfer).isEncapsulated()) {
+    if (DcmXfer(xfer).usesEncapsulatedFormat()) {
         DcmRepresentationListIterator found;
         OFCondition cond = findConformingEncapsulatedRepresentation(xfer, NULL, found);
         if (cond.good()) {
diff --git a/dcmdata/libsrc/dcpixseq.cc b/dcmdata/libsrc/dcpixseq.cc
index 1af63add22..7d81fb6803 100644
--- a/dcmdata/libsrc/dcpixseq.cc
+++ b/dcmdata/libsrc/dcpixseq.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 1994-2023, OFFIS e.V.
+ *  Copyright (C) 1994-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -341,7 +341,7 @@ OFBool DcmPixelSequence::canWriteXfer(const E_TransferSyntax newXfer,
 {
     DcmXfer newXferSyn(newXfer);
 
-    return newXferSyn.isEncapsulated() && newXfer == oldXfer && oldXfer == Xfer;
+    return newXferSyn.usesEncapsulatedFormat() && newXfer == oldXfer && oldXfer == Xfer;
 }
 
 
diff --git a/dcmdata/libsrc/dcrleccd.cc b/dcmdata/libsrc/dcrleccd.cc
index 8c0421169e..86e62099a4 100644
--- a/dcmdata/libsrc/dcrleccd.cc
+++ b/dcmdata/libsrc/dcrleccd.cc
@@ -52,7 +52,8 @@ OFBool DcmRLECodecDecoder::canChangeCoding(
 {
   E_TransferSyntax myXfer = EXS_RLELossless;
   DcmXfer newRep(newRepType);
-  if (newRep.isNotEncapsulated() && (oldRepType == myXfer)) return OFTrue; // decompress requested
+  if (newRep.usesNativeFormat() && (oldRepType == myXfer))
+    return OFTrue; // decompress requested
 
   // we don't support re-coding for now.
   return OFFalse;
diff --git a/dcmdata/libsrc/dcrlecce.cc b/dcmdata/libsrc/dcrlecce.cc
index 3c017354db..ef835f4edd 100644
--- a/dcmdata/libsrc/dcrlecce.cc
+++ b/dcmdata/libsrc/dcrlecce.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 2002-2021, OFFIS e.V.
+ *  Copyright (C) 2002-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -55,7 +55,7 @@ OFBool DcmRLECodecEncoder::canChangeCoding(
   E_TransferSyntax myXfer = EXS_RLELossless;
   DcmXfer newRep(newRepType);
   DcmXfer oldRep(oldRepType);
-  if (oldRep.isNotEncapsulated() && (newRepType == myXfer)) return OFTrue; // compress requested
+  if (oldRep.usesNativeFormat() && (newRepType == myXfer)) return OFTrue; // compress requested
 
   // we don't support re-coding for now.
   return OFFalse;
diff --git a/dcmdata/libsrc/dcvrobow.cc b/dcmdata/libsrc/dcvrobow.cc
index 39d8a37923..3273998455 100644
--- a/dcmdata/libsrc/dcvrobow.cc
+++ b/dcmdata/libsrc/dcvrobow.cc
@@ -655,7 +655,8 @@ OFBool DcmOtherByteOtherWord::canWriteXfer(const E_TransferSyntax newXfer,
                                            const E_TransferSyntax /*oldXfer*/)
 {
     DcmXfer newXferSyn(newXfer);
-    return (getTag() != DCM_PixelData) || !newXferSyn.isEncapsulated();
+    /* pixel data can only be written in native format */
+    return (getTag() != DCM_PixelData) || newXferSyn.usesNativeFormat();
 }
 
 
diff --git a/dcmect/libsrc/enhanced_ct.cc b/dcmect/libsrc/enhanced_ct.cc
index cffd610a86..f613850faa 100644
--- a/dcmect/libsrc/enhanced_ct.cc
+++ b/dcmect/libsrc/enhanced_ct.cc
@@ -1225,9 +1225,9 @@ OFCondition EctEnhancedCT::decompress(DcmDataset& dset)
 {
     DcmXfer xfer = dset.getOriginalXfer();
     OFCondition result;
-    // If the original transfer is encapsulated and we do not already have an uncompressed version, decompress or reject
-    // the file
-    if (xfer.isEncapsulated())
+    // If the original transfer syntax refers to compressed pixel data and we do not
+    // already have an uncompressed version, decompress or reject the file
+    if (xfer.isPixelDataCompressed())
     {
         DCMECT_DEBUG("Enhanced CT object is compressed, converting to uncompressed transfer syntax first");
         result = DcmIODUtil::decompress(dset);
diff --git a/dcmimgle/include/dcmtk/dcmimgle/didocu.h b/dcmimgle/include/dcmtk/dcmimgle/didocu.h
index 4aab11433b..8187949a12 100644
--- a/dcmimgle/include/dcmtk/dcmimgle/didocu.h
+++ b/dcmimgle/include/dcmtk/dcmimgle/didocu.h
@@ -179,7 +179,7 @@ class DCMTK_DCMIMGLE_EXPORT DiDocument
      */
     inline OFBool isCompressed() const
     {
-        return DcmXfer(Xfer).isEncapsulated();
+        return DcmXfer(Xfer).isPixelDataCompressed();
     }
 
     /** search for given tag
diff --git a/dcmimgle/libsrc/didocu.cc b/dcmimgle/libsrc/didocu.cc
index efbbd69fbd..a0db6ec973 100644
--- a/dcmimgle/libsrc/didocu.cc
+++ b/dcmimgle/libsrc/didocu.cc
@@ -126,16 +126,16 @@ void DiDocument::convertPixelData()
             if (pobject->ident() == EVR_PixelData)
             {
                 PixelData = OFstatic_cast(DcmPixelData *, pobject);
-                // check for a special (faulty) case where the original pixel data is uncompressed and
-                // the transfer syntax of the dataset refers to encapsulated format (i.e. compression)
+                // check for a special (faulty) case where the original pixel data is uncompressed in
+                // native format and the transfer syntax of the dataset refers to encapsulated format
                 if (Object->ident() == EVR_dataset)
                 {
                     E_TransferSyntax repType = EXS_Unknown;
                     const DcmRepresentationParameter *repParam = NULL;
                     PixelData->getOriginalRepresentationKey(repType, repParam);
-                    if (xfer.isEncapsulated() && !DcmXfer(repType).isEncapsulated())
+                    if (xfer.usesEncapsulatedFormat() && DcmXfer(repType).usesNativeFormat())
                     {
-                        DCMIMGLE_WARN("pixel data is stored in uncompressed format, although "
+                        DCMIMGLE_WARN("pixel data is stored in native format, although "
                             << "the transfer syntax of the dataset refers to encapsulated format");
                     }
                 }
@@ -160,8 +160,8 @@ void DiDocument::convertPixelData()
                     }
                     if (status.good())
                     {
-                        // set transfer syntax to unencapsulated/uncompressed
-                        if (xfer.isEncapsulated())
+                        // set transfer syntax to native format (uncompressed pixel data)
+                        if (xfer.usesEncapsulatedFormat())
                         {
                             Xfer = EXS_LittleEndianExplicit;
                             DCMIMGLE_DEBUG("decompressed complete pixel data in memory: " << PixelData->getLength(Xfer) << " bytes");
diff --git a/dcmiod/libsrc/iodutil.cc b/dcmiod/libsrc/iodutil.cc
index 64c985cb50..0827d27e5e 100644
--- a/dcmiod/libsrc/iodutil.cc
+++ b/dcmiod/libsrc/iodutil.cc
@@ -643,7 +643,7 @@ const DcmTagKey DcmIODUtil::parseTagKey(const OFString& keyString)
 OFCondition DcmIODUtil::decompress(DcmDataset& dset)
 {
     DcmXfer xfer = dset.getOriginalXfer();
-    if (xfer.isEncapsulated())
+    if (xfer.isPixelDataCompressed())
     {
         if (EC_Normal != dset.chooseRepresentation(EXS_LittleEndianExplicit, NULL))
         {
diff --git a/dcmjpeg/apps/dcmcjpeg.cc b/dcmjpeg/apps/dcmcjpeg.cc
index 7c7cba15a2..cbb5eb4ca5 100644
--- a/dcmjpeg/apps/dcmcjpeg.cc
+++ b/dcmjpeg/apps/dcmcjpeg.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 2001-2022, OFFIS e.V.
+ *  Copyright (C) 2001-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -679,7 +679,7 @@ int main(int argc, char *argv[])
     DcmDataset *dataset = fileformat.getDataset();
 
     DcmXfer original_xfer(dataset->getOriginalXfer());
-    if (original_xfer.isEncapsulated())
+    if (original_xfer.isPixelDataCompressed())
     {
       OFLOG_INFO(dcmcjpegLogger, "DICOM file is already compressed, converting to uncompressed transfer syntax first");
       if (EC_Normal != dataset->chooseRepresentation(EXS_LittleEndianExplicit, NULL))
diff --git a/dcmjpeg/libsrc/djcodecd.cc b/dcmjpeg/libsrc/djcodecd.cc
index c06300f85a..5b0eeea213 100644
--- a/dcmjpeg/libsrc/djcodecd.cc
+++ b/dcmjpeg/libsrc/djcodecd.cc
@@ -54,7 +54,8 @@ OFBool DJCodecDecoder::canChangeCoding(
 {
   E_TransferSyntax myXfer = supportedTransferSyntax();
   DcmXfer newRep(newRepType);
-  if (newRep.isNotEncapsulated() && (oldRepType == myXfer)) return OFTrue; // decompress requested
+  if (newRep.usesNativeFormat() && (oldRepType == myXfer))
+    return OFTrue; // decompress requested
 
   // we don't support re-coding for now.
   return OFFalse;
diff --git a/dcmjpeg/libsrc/djcodece.cc b/dcmjpeg/libsrc/djcodece.cc
index d0371f6c2b..de973c5db3 100644
--- a/dcmjpeg/libsrc/djcodece.cc
+++ b/dcmjpeg/libsrc/djcodece.cc
@@ -67,7 +67,8 @@ OFBool DJCodecEncoder::canChangeCoding(
   E_TransferSyntax myXfer = supportedTransferSyntax();
   DcmXfer newRep(newRepType);
   DcmXfer oldRep(oldRepType);
-  if (oldRep.isNotEncapsulated() && (newRepType == myXfer)) return OFTrue; // compress requested
+  if (oldRep.usesNativeFormat() && (newRepType == myXfer))
+    return OFTrue; // compress requested
 
   // we don't support re-coding for now
   return OFFalse;
diff --git a/dcmjpls/apps/dcmcjpls.cc b/dcmjpls/apps/dcmcjpls.cc
index 6921f71dab..4c5cdf5aa1 100644
--- a/dcmjpls/apps/dcmcjpls.cc
+++ b/dcmjpls/apps/dcmcjpls.cc
@@ -1,6 +1,6 @@
 /*
  *
- *  Copyright (C) 2007-2022, OFFIS e.V.
+ *  Copyright (C) 2007-2024, OFFIS e.V.
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation were developed by
@@ -437,7 +437,7 @@ LICENSE_FILE_EVALUATE_COMMAND_LINE_OPTIONS
     DcmDataset *dataset = fileformat.getDataset();
 
     DcmXfer original_xfer(dataset->getOriginalXfer());
-    if (original_xfer.isEncapsulated())
+    if (original_xfer.isPixelDataCompressed())
     {
       OFLOG_INFO(dcmcjplsLogger, "DICOM file is already compressed, converting to uncompressed transfer syntax first");
       if (EC_Normal != dataset->chooseRepresentation(EXS_LittleEndianExplicit, NULL))
diff --git a/dcmjpls/libsrc/djcodecd.cc b/dcmjpls/libsrc/djcodecd.cc
index e2a3ea4436..ca549afdb9 100644
--- a/dcmjpls/libsrc/djcodecd.cc
+++ b/dcmjpls/libsrc/djcodecd.cc
@@ -69,7 +69,7 @@ OFBool DJLSDecoderBase::canChangeCoding(
   // this codec only handles conversion from JPEG-LS to uncompressed.
 
   DcmXfer newRep(newRepType);
-  if (newRep.isNotEncapsulated() && (oldRepType == supportedTransferSyntax()))
+  if (newRep.usesNativeFormat() && (oldRepType == supportedTransferSyntax()))
      return OFTrue;
 
   return OFFalse;
diff --git a/dcmjpls/libsrc/djcodece.cc b/dcmjpls/libsrc/djcodece.cc
index eba1210c96..adf5dbb156 100644
--- a/dcmjpls/libsrc/djcodece.cc
+++ b/dcmjpls/libsrc/djcodece.cc
@@ -96,7 +96,7 @@ OFBool DJLSEncoderBase::canChangeCoding(
 {
   // this codec only handles conversion from uncompressed to JPEG-LS.
   DcmXfer oldRep(oldRepType);
-  return (oldRep.isNotEncapsulated() && (newRepType == supportedTransferSyntax()));
+  return (oldRep.usesNativeFormat() && (newRepType == supportedTransferSyntax()));
 }
 
 
diff --git a/dcmnet/apps/getscu.cc b/dcmnet/apps/getscu.cc
index f83e797b9c..e182adb1db 100644
--- a/dcmnet/apps/getscu.cc
+++ b/dcmnet/apps/getscu.cc
@@ -603,7 +603,7 @@ static void prepareTS(E_TransferSyntax ts,
 #endif
     default:
       DcmXfer xfer(ts);
-      if (xfer.isEncapsulated())
+      if (xfer.usesEncapsulatedFormat())
       {
         syntaxes.push_back(xfer.getXferID());
       }
diff --git a/dcmnet/apps/storescu.cc b/dcmnet/apps/storescu.cc
index f90d445988..306b941905 100644
--- a/dcmnet/apps/storescu.cc
+++ b/dcmnet/apps/storescu.cc
@@ -1333,11 +1333,11 @@ storeSCU(T_ASC_Association *assoc, const char *fname)
   /* figure out which of the accepted presentation contexts should be used */
   DcmXfer filexfer(dcmff.getDataset()->getOriginalXfer());
 
-  /* special case: if the file uses an unencapsulated transfer syntax (uncompressed
-   * or deflated explicit VR) and we prefer deflated explicit VR, then try
-   * to find a presentation context for deflated explicit VR first.
+  /* special case: if the file uses a transfer syntax with native format
+   * (uncompressed or deflated explicit VR) and we prefer deflated explicit VR,
+   * then try to find a presentation context for deflated explicit VR first.
    */
-  if (filexfer.isNotEncapsulated() &&
+  if (filexfer.usesNativeFormat() &&
     opt_networkTransferSyntax == EXS_DeflatedLittleEndianExplicit)
   {
     filexfer = EXS_DeflatedLittleEndianExplicit;
diff --git a/dcmpmap/libsrc/dpmparametricmapiod.cc b/dcmpmap/libsrc/dpmparametricmapiod.cc
index 857b50b745..9301e3faa7 100644
--- a/dcmpmap/libsrc/dpmparametricmapiod.cc
+++ b/dcmpmap/libsrc/dpmparametricmapiod.cc
@@ -993,15 +993,16 @@ OFCondition DPMParametricMapIOD::decompress(DcmDataset& dset)
   // If the original transfer syntax could have been lossy, print warning
   if (dset.hasRepresentation(EXS_LittleEndianExplicit, NULL))
   {
-    if ( xfer.isEncapsulated() && (xfer != EXS_RLELossless) && (xfer != EXS_DeflatedLittleEndianExplicit) )
+    if (xfer.isPixelDataCompressed() && (xfer != EXS_RLELossless))
     {
       DCMPMAP_WARN("Dataset has been compressed using a (possibly) lossy compression scheme (ignored)");
     }
   }
-  // If the original transfer is encapsulated and we do not already have an uncompressed version, decompress or reject the file
-  else if (xfer.isEncapsulated())
+  // If the original transfer syntax refers to compressed pixel data and we do not
+  // already have an uncompressed version, decompress or reject the file
+  else if (xfer.isPixelDataCompressed())
   {
-    // RLE compression is fine (truly lossless). Deflated is handled internally by DCMTK.
+    // RLE compression is fine (truly lossless)
     if (xfer == EXS_RLELossless)
     {
       DCMPMAP_DEBUG("DICOM file is RLE-compressed, converting to uncompressed transfer syntax first");
diff --git a/dcmseg/libsrc/segdoc.cc b/dcmseg/libsrc/segdoc.cc
index a028349e17..89868fccf3 100644
--- a/dcmseg/libsrc/segdoc.cc
+++ b/dcmseg/libsrc/segdoc.cc
@@ -1403,16 +1403,16 @@ OFCondition DcmSegmentation::decompress(DcmDataset& dset)
     // If the original transfer syntax could have been lossy, print warning
     if (dset.hasRepresentation(EXS_LittleEndianExplicit, NULL))
     {
-        if (xfer.isEncapsulated() && (xfer != EXS_RLELossless) && (xfer != EXS_DeflatedLittleEndianExplicit))
+        if (xfer.isPixelDataCompressed() && (xfer != EXS_RLELossless))
         {
             DCMSEG_WARN("Dataset has been compressed using a (possibly) lossy compression scheme (ignored)");
         }
     }
-    // If the original transfer is encapsulated and we do not already have an uncompressed version, decompress or reject
-    // the file
-    else if (xfer.isEncapsulated())
+    // If the original transfer syntax refers to compressed pixel data and we do not
+    // already have an uncompressed version, decompress or reject the file
+    else if (xfer.isPixelDataCompressed())
     {
-        // RLE compression is fine (truly lossless). Deflated is handled internally by DCMTK.
+        // RLE compression is fine (truly lossless)
         if (xfer == EXS_RLELossless)
         {
             DCMSEG_DEBUG("DICOM file is RLE-compressed, converting to uncompressed transfer syntax first");
diff --git a/dcmtract/libsrc/trctractographyresults.cc b/dcmtract/libsrc/trctractographyresults.cc
index 9c83e10269..17a8249fd1 100644
--- a/dcmtract/libsrc/trctractographyresults.cc
+++ b/dcmtract/libsrc/trctractographyresults.cc
@@ -1,6 +1,6 @@
   /*
  *
- *  Copyright (C) 2016-2018, Open Connections GmbH
+ *  Copyright (C) 2016-2024, Open Connections GmbH
  *  All rights reserved.  See COPYRIGHT file for details.
  *
  *  This software and supporting documentation are maintained by
@@ -71,8 +71,8 @@ OFCondition TrcTractographyResults::loadDataset(
   TrcTractographyResults*& tract)
 {
   DcmXfer xfer = dataset.getOriginalXfer();
-  // If the original transfer is encapsulated and we do not already have an uncompressed version, decompress or reject the file
-  if (xfer.isEncapsulated())
+  // If the original transfer syntax refers to compressed pixel data reject the file
+  if (xfer.isPixelDataCompressed())
   {
     DCMTRACT_ERROR("Cannot load dataset since it is compressed, transfer syntax: " << xfer.getXferName());
     return IOD_EC_CannotDecompress;