Add t35_identifier_length and move descr to hrsd

Author: y-guyon

IsoLib/isoiff_tool/w32/isoiff/isoiff.dsp

@@ -71,6 +71,7 @@ add_library(
     src/H263SpecificInfoAtom.c
     src/HandlerAtom.c
     src/HEVCConfigAtom.c
+    src/HumanReadableStreamDescriptionAtom.c
     src/LHEVCConfigAtom.c
     src/VVCConfigAtom.c
     src/VVCNALUConfigAtom.c

IsoLib/libisomediafile/CMakeLists.txt

@@ -158,6 +158,7 @@ sources = \
 	TextMetaSampleEntry.c \
 	XMLMetaSampleEntry.c \
 	BitRateAtom.c \
+	HumanReadableStreamDescriptionAtom.c \
 	AMRWPSpecificInfoAtom.c \
 	AMRSpecificInfoAtom.c \
 	H263SpecificInfoAtom.c \

IsoLib/libisomediafile/linux/libisomediafile/Makefile

@@ -158,6 +158,7 @@ sources = \
 	TextMetaSampleEntry.c \
 	XMLMetaSampleEntry.c \
 	BitRateAtom.c \
+	HumanReadableStreamDescriptionAtom.c \
 	AMRWPSpecificInfoAtom.c \
 	AMRSpecificInfoAtom.c \
 	H263SpecificInfoAtom.c \

IsoLib/libisomediafile/macosx/libisomediafile/Makefile

@@ -0,0 +1,165 @@
+/*
+Copyright 2026 Google LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include "MP4Atoms.h"
+#include <stdlib.h>
+
+static void destroy(MP4AtomPtr s)
+{
+  MP4HumanReadableStreamDescriptionAtomPtr self;
+  self = (MP4HumanReadableStreamDescriptionAtomPtr)s;
+  if(self == NULL) return;
+
+  if(self->description)
+  {
+    free(self->description);
+    self->description = NULL;
+  }
+
+  if(self->super) self->super->destroy(s);
+}
+
+static MP4Err serialize(struct MP4Atom *s, char *buffer)
+{
+  MP4Err err;
+  MP4HumanReadableStreamDescriptionAtomPtr self = (MP4HumanReadableStreamDescriptionAtomPtr)s;
+  err                                           = MP4NoErr;
+
+  err = MP4SerializeCommonBaseAtomFields(s, buffer);
+  if(err) goto bail;
+  buffer += self->bytesWritten;
+  assert(self->type == MP4HumanReadableStreamDescriptionAtomType);
+
+  /* Write description as null-terminated UTF-8 string */
+  if(self->description != NULL)
+  {
+    u32 descLen = (u32)strlen(self->description) + 1; /* Include null terminator */
+    PUTBYTES(self->description, descLen);
+  }
+  else
+  {
+    /* Empty description: just write '\0' */
+    u8 nullByte = 0;
+    PUT8_V(nullByte);
+  }
+
+  assert(self->bytesWritten == self->size);
+bail:
+  TEST_RETURN(err);
+
+  return err;
+}
+
+static MP4Err calculateSize(struct MP4Atom *s)
+{
+  MP4Err err;
+  MP4HumanReadableStreamDescriptionAtomPtr self = (MP4HumanReadableStreamDescriptionAtomPtr)s;
+  err                                           = MP4NoErr;
+
+  err = MP4CalculateBaseAtomFieldSize(s);
+  if(err) goto bail;
+  /* Add description size (null-terminated string) */
+  if(self->description != NULL)
+  {
+    self->size += (u32)strlen(self->description) + 1; /* Including '\0' */
+  }
+  else
+  {
+    self->size += 1; /* Just '\0' */
+  }
+bail:
+  TEST_RETURN(err);
+
+  return err;
+}
+
+static MP4Err createFromInputStream(MP4AtomPtr s, MP4AtomPtr proto, MP4InputStreamPtr inputStream)
+{
+  MP4Err err;
+  MP4HumanReadableStreamDescriptionAtomPtr self = (MP4HumanReadableStreamDescriptionAtomPtr)s;
+  s64 bytesToRead;
+  u32 nullPos;
+  u32 descLen;
+  u8 *buf = NULL;
+  u32 i;
+
+  if(self == NULL) BAILWITHERROR(MP4BadParamErr)
+  err = self->super->createFromInputStream(s, proto, (char *)inputStream);
+  if(err) goto bail;
+
+  /* Read all remaining bytes into a flat buffer, then split on the first null byte.
+   * Scanning byte-by-byte and "rewinding" by adjusting only bytesRead (while leaving
+   * the stream cursor in place) does not work — readData always reads from the current
+   * stream position. */
+  bytesToRead = (s64)(self->size - self->bytesRead);
+  if(bytesToRead < 0) BAILWITHERROR(MP4BadDataErr);
+
+  if(bytesToRead > 0)
+  {
+    buf = (u8 *)calloc((u32)bytesToRead, 1);
+    TESTMALLOC(buf);
+    err = inputStream->readData(inputStream, (u32)bytesToRead, (char *)buf, NULL);
+    if(err) goto bail;
+    self->bytesRead += (u32)bytesToRead;
+
+    /* Find the null terminator that ends the description field */
+    nullPos = (u32)bytesToRead; /* default: no null found */
+    for(i = 0; i < (u32)bytesToRead; i++)
+    {
+      if(buf[i] == 0)
+      {
+        nullPos = i;
+        break;
+      }
+    }
+
+    /* Description: bytes [0 .. nullPos] (including the null terminator) */
+    descLen           = nullPos + 1; /* length including null */
+    self->description = (char *)calloc(descLen, 1);
+    TESTMALLOC(self->description);
+    memcpy(self->description, buf, descLen);
+  }
+
+bail:
+  free(buf);
+  TEST_RETURN(err);
+  return err;
+}
+
+MP4Err
+MP4CreateHumanReadableStreamDescriptionAtom(MP4HumanReadableStreamDescriptionAtomPtr *outAtom)
+{
+  MP4Err err;
+  MP4HumanReadableStreamDescriptionAtomPtr self;
+
+  self = (MP4HumanReadableStreamDescriptionAtomPtr)calloc(
+    1, sizeof(MP4HumanReadableStreamDescriptionAtom));
+  TESTMALLOC(self);
+
+  err = MP4CreateBaseAtom((MP4AtomPtr)self);
+  if(err) goto bail;
+  self->type                  = MP4HumanReadableStreamDescriptionAtomType;
+  self->name                  = "HumanReadableStreamDescription";
+  self->createFromInputStream = (cisfunc)createFromInputStream;
+  self->destroy               = destroy;
+  self->calculateSize         = calculateSize;
+  self->serialize             = serialize;
+  *outAtom                    = self;
+bail:
+  TEST_RETURN(err);
+
+  return err;
+}

IsoLib/libisomediafile/src/HumanReadableStreamDescriptionAtom.c

@@ -877,20 +877,16 @@ extern "C"
    * @ingroup SampleDescr
    *
    * Properly deserializes the handle returned by MP4GetMediaSampleDescription() and extracts
-   * the T.35 identifier bytes and optional description string. The caller is responsible for
-   * freeing *outIdentifier and *outDescription with free().
+   * the T.35 identifier bytes. The caller is responsible for freeing *outIdentifier with free().
    *
    * @param sampleEntryH  Handle containing the serialized 'it35' sample entry.
    * @param outIdentifier Output; receives a newly allocated copy of the t35_identifier bytes.
-   * @param outIdentifierSize Output; receives the number of bytes in *outIdentifier.
-   * @param outDescription Optional output; receives a newly allocated description string, or NULL
-   *                       if no description is present. Pass NULL to ignore.
+   * @param outIdentifierLength Output; receives the number of bytes in *outIdentifier.
    * @return MP4NoErr on success, MP4NotFoundErr if no identifier is present, MP4BadParamErr on
    *         invalid input.
    */
   ISO_EXTERN(ISOErr)
-  ISOGetT35SampleEntryFields(MP4Handle sampleEntryH, u8 **outIdentifier, u32 *outIdentifierSize,
-                             char **outDescription);
+  ISOGetT35SampleEntryFields(MP4Handle sampleEntryH, u8 **outIdentifier, u32 *outIdentifierLength);
 
   /*************************************************************************************************
    * VVC Sample descriptions