From b7c35e5a0d274645c6723e3f9425f43b0c0a26fc Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <mo@bunkus.online>
Date: Sat, 20 Mar 2021 16:52:17 +0100
Subject: [PATCH] a script for extracting NALUs from h.265 bitstreams via
 hevc_dump

---
 src/tools/hevc_extract_nalus.rb | 35 +++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100755 src/tools/hevc_extract_nalus.rb

diff --git a/src/tools/hevc_extract_nalus.rb b/src/tools/hevc_extract_nalus.rb
new file mode 100755
index 000000000..9da50e587
--- /dev/null
+++ b/src/tools/hevc_extract_nalus.rb
@@ -0,0 +1,35 @@
+#!/usr/bin/env ruby
+
+require "pp"
+require "shellwords"
+
+if ARGV.size < 2
+  puts "Need two arguments: source file name & base name for NALUs"
+  exit 1
+end
+
+nalus = []
+
+`hevc_dump #{Shellwords.escape(ARGV[0])}`.
+  split(%r{\n+}).
+  each do |line|
+
+  if %r{size (\d+) (?:marker size (\d+) )?at (\d+)}.match(line)
+    # NALU type 0x00 (trail_n) size 10609 marker size 4 at 985088 checksum 0x4093bba9
+    nalus << [ $1.to_i, $3.to_i + ($2 && !$2.empty? ? $2.to_i : 0) ]
+  end
+end
+
+src_file     = File.open(ARGV[0], 'rb') || fail("Could not open #{ARGV[0]}")
+dst_file_num = 0
+
+nalus.each do |nalu|
+  dst_file_name = sprintf ARGV[1], dst_file_num
+  dst_file_num += 1
+  dst_file      = File.open(dst_file_name, 'wb') || fail("Could not create #{dst_file_name}")
+
+  src_file.seek(nalu[1])
+  content = src_file.read(nalu[0])
+  dst_file.write(content)
+  dst_file.close
+end