Various changes:

1. Use Process.waitFor (works better with graal)
2. Extract start timecode of first frame of each partition
3. Use start datetime when building filename for partition output

src/main/java/Remux.java

@@ -37,19 +37,23 @@ public static void main(String[] args) throws Exception
 
 		System.out.println("Frame info parsed, extracting video frames...");
 
-		final boolean multipartition = partitions.size() > 1;
-
 		for (UbvPartition partition : partitions)
 		{
-			final String outputBasename = (multipartition) ? (inputFile.getName() + ".p" + partition.index) : inputFile.getName();
+			final File videoOutput = new File(inputFile.getParent(), getOutputFilename(inputFile, partition));
 
-			final File h264Stream = new File(inputFile.getParent(), outputBasename + ".h264");
+			System.out.println("Extracting video starting at " + partition.firstFrameTimecode + " to " + videoOutput);
 
-			extractPrimitiveVideoStream(inputFile, h264Stream, partition.frames);
+			extractPrimitiveVideoStream(inputFile, videoOutput, partition.frames);
 		}
 	}
 
 
+	private static String getOutputFilename(final File inputFile, final UbvPartition partition)
+	{
+		return inputFile.getName() + "." + partition.firstFrameTimecode.toString().replaceAll("[:+]", ".") + ".h264";
+	}
+
+
 	private static Stream<String> ubvinfo(final File inputFile) throws IOException, InterruptedException
 	{
 		// Write ubvinfo to a temporary file
@@ -63,14 +67,10 @@ private static Stream<String> ubvinfo(final File inputFile) throws IOException,
 			pb.redirectOutput(tempFile);
 			Process process = pb.start();
 
-			long timeout = System.currentTimeMillis() + MAX_UBVINFO_RUNTIME; // Wait 2 minutes at most
-			while (process.isAlive() && System.currentTimeMillis() > timeout)
-			{
-				Thread.sleep(1000);
-			}
+			final int exitCode = process.waitFor();
 
-			if (process.exitValue() != 0)
-				throw new IllegalArgumentException("ubvinfo failed!");
+			if (exitCode != 0)
+				throw new IllegalArgumentException("ubvinfo failed with code " + exitCode);
 
 			return Files.lines(tempFile.toPath());
 		}
@@ -105,7 +105,6 @@ private static int extractPrimitiveVideoStream(final File inputFile,
 							final int frameOffset = dataref.offset;
 							final int frameLength = dataref.size;
 
-							// TODO for video: process NALs (ubv format uses length prefixes rather than NAL separators)
 							// TODO for audio: simply extract the raw data
 							if (video)
 							{

src/main/java/UbvInfoParser.java

@@ -1,13 +1,20 @@
+import java.time.Instant;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
+import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
 public class UbvInfoParser
 {
 	private static final String PARTITION_START = "----------- PARTITION START -----------";
 	private static final int FIELD_OFFSET = 4;
 	private static final int FIELD_SIZE = 5;
+	private static final int FIELD_WC = 8;
+	private static final int FIELD_WC_TBC = 9;
+
+	private static final Pattern REGEX_SPACES = Pattern.compile(" +");
 
 
 	/**
@@ -42,11 +49,35 @@ else if (line.equals(PARTITION_START))
 			}
 			else if (Character.isWhitespace(line.charAt(0)))
 			{
-				final String[] fields = line.split(" +", 7);
-				final int offset = Integer.parseInt(fields[FIELD_OFFSET]);
-				final int size = Integer.parseInt(fields[FIELD_SIZE]);
+				final String[] fields;
+				if (current.firstFrameTimecode == null)
+				{
+					fields = REGEX_SPACES.split(line);
+
+					final long wc = Long.parseLong(fields[FIELD_WC]);
+					final int tbc = Integer.parseInt(fields[FIELD_WC_TBC]);
+
+					if (tbc >= 1000)
+					{
+						current.firstFrameTimecode = Instant.ofEpochMilli(wc / (tbc / 1000)); // Convert wc to utc millis
+					}
+				}
+				else
+				{
+					fields = REGEX_SPACES.split(line, FIELD_SIZE + 2);
+				}
+
+				try
+				{
+					final int offset = Integer.parseInt(fields[FIELD_OFFSET]);
+					final int size = Integer.parseInt(fields[FIELD_SIZE]);
 
-				current.frames.add(new FrameDataRef(offset, size));
+					current.frames.add(new FrameDataRef(offset, size));
+				}
+				catch (Throwable t)
+				{
+					throw new RuntimeException("Error parsing " + Arrays.asList(fields) + ": " + t.getMessage(), t);
+				}
 			}
 		}
 

src/main/java/UbvPartition.java

@@ -1,9 +1,11 @@
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 
 public class UbvPartition
 {
 	public final int index;
+	public Instant firstFrameTimecode;
 	public final List<FrameDataRef> frames = new ArrayList<>();
 
 

src/test/java/UbvInfoParserTest.java

@@ -3,6 +3,7 @@
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.time.Instant;
 import java.util.List;
 import java.util.stream.Stream;
 import java.util.zip.GZIPInputStream;
@@ -11,13 +12,28 @@
 
 public class UbvInfoParserTest
 {
+	/**
+	 *
+	 */
+	@Test
+	public void testDateTimeParse()
+	{
+		final Instant instantFromFilename = Instant.ofEpochMilli(1556890741069L);
+		final Instant instantFromWcColumn = Instant.ofEpochMilli(1556888562619L);
+
+		assertEquals("2019-05-03T13:39:01.069Z", instantFromFilename.toString());
+		assertEquals("2019-05-03T13:02:42.619Z", instantFromWcColumn.toString());
+	}
+
+
 	@Test
 	public void testSinglePartitionFile() throws IOException
 	{
 		final List<UbvPartition> partitions = UbvInfoParser.parse(readCompressedInfoFile(
 				"/FCECFFFFFFFF_2_rotating_1596209441895.ubv.txt.gz"));
 
 		assertEquals("expected partition count", 1, partitions.size());
+		assertEquals("first partition first frame timecode", Instant.parse("2020-07-31T15:30:36.046Z"), partitions.get(0).firstFrameTimecode);
 		assertEquals("frames in partition 1", 239194, partitions.get(0).frames.size());
 	}