webm2pes: Add a WebM parser init method.

Pre-refactor a little to avoid some code duplication.

Change-Id: I8ce733be0c9e07544fc25bd9890d68fb14a7e84d

webm2pes.cc

@@ -249,12 +249,6 @@ bool Webm2Pes::ConvertToFile() {
     return false;
   }
 
-  if (webm_reader_.Open(input_file_name_.c_str()) != 0) {
-    std::fprintf(stderr, "Webm2Pes: Cannot open %s as input.\n",
-                 input_file_name_.c_str());
-    return false;
-  }
-
   output_file_ = FilePtr(fopen(output_file_name_.c_str(), "wb"), FILEDeleter());
   if (output_file_ == nullptr) {
     std::fprintf(stderr, "Webm2Pes: Cannot open %s for output.\n",
@@ -262,6 +256,62 @@ bool Webm2Pes::ConvertToFile() {
     return false;
   }
 
+  if (InitWebmParser() != true) {
+    std::fprintf(stderr, "Webm2Pes: Cannot initialize WebM parser.\n");
+    return false;
+  }
+
+  // Walk clusters in segment.
+  const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
+  while (cluster != nullptr && cluster->EOS() == false) {
+    const mkvparser::BlockEntry* block_entry = nullptr;
+    std::int64_t block_status = cluster->GetFirst(block_entry);
+    if (block_status < 0) {
+      std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
+                   input_file_name_.c_str());
+      return false;
+    }
+
+    // Walk blocks in cluster.
+    while (block_entry != nullptr && block_entry->EOS() == false) {
+      const mkvparser::Block* block = block_entry->GetBlock();
+      if (block->GetTrackNumber() == video_track_num_) {
+        const int frame_count = block->GetFrameCount();
+
+        // Walk frames in block.
+        for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
+          const mkvparser::Block::Frame& frame = block->GetFrame(frame_num);
+
+          // Write frame out as PES packet(s).
+          const bool pes_status =
+              WritePesPacket(frame, block->GetTime(cluster));
+          if (pes_status != true) {
+            std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
+            return false;
+          }
+        }
+      }
+      block_status = cluster->GetNext(block_entry, block_entry);
+      if (block_status < 0) {
+        std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
+                     input_file_name_.c_str());
+        return false;
+      }
+    }
+
+    cluster = webm_parser_->GetNext(cluster);
+  }
+
+  return true;
+}
+
+bool Webm2Pes::InitWebmParser() {
+  if (webm_reader_.Open(input_file_name_.c_str()) != 0) {
+    std::fprintf(stderr, "Webm2Pes: Cannot open %s as input.\n",
+                 input_file_name_.c_str());
+    return false;
+  }
+
   using mkvparser::Segment;
   Segment* webm_parser = nullptr;
   if (Segment::CreateInstance(&webm_reader_, 0 /* pos */,
@@ -308,48 +358,6 @@ bool Webm2Pes::ConvertToFile() {
                  input_file_name_.c_str());
     return false;
   }
-
-  // Walk clusters in segment.
-  const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
-  while (cluster != nullptr && cluster->EOS() == false) {
-    const mkvparser::BlockEntry* block_entry = nullptr;
-    std::int64_t block_status = cluster->GetFirst(block_entry);
-    if (block_status < 0) {
-      std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
-                   input_file_name_.c_str());
-      return false;
-    }
-
-    // Walk blocks in cluster.
-    while (block_entry != nullptr && block_entry->EOS() == false) {
-      const mkvparser::Block* block = block_entry->GetBlock();
-      if (block->GetTrackNumber() == video_track_num_) {
-        const int frame_count = block->GetFrameCount();
-
-        // Walk frames in block.
-        for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
-          const mkvparser::Block::Frame& frame = block->GetFrame(frame_num);
-
-          // Write frame out as PES packet(s).
-          const bool pes_status =
-              WritePesPacket(frame, block->GetTime(cluster));
-          if (pes_status != true) {
-            std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
-            return false;
-          }
-        }
-      }
-      block_status = cluster->GetNext(block_entry, block_entry);
-      if (block_status < 0) {
-        std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
-                     input_file_name_.c_str());
-        return false;
-      }
-    }
-
-    cluster = webm_parser_->GetNext(cluster);
-  }
-
   return true;
 }
 
@@ -430,4 +438,3 @@ bool Webm2Pes::WritePesPacket(const mkvparser::Block::Frame& vpx_frame,
   return true;
 }
 }  // namespace libwebm
-

webm2pes.h

@@ -184,6 +184,7 @@ class Webm2Pes {
   };
   typedef std::unique_ptr<FILE, FILEDeleter> FilePtr;
 
+  bool InitWebmParser();
   bool WritePesPacket(const mkvparser::Block::Frame& vpx_frame,
                       double nanosecond_pts);