With this utility you can split a raw h264 file into chunk files with one NAL unit each.

Once this repository is cloned, type the following on terminal to create the executable h264Splitter3 and h264Splitter4

make all

• h264Splitter3 for 001 header starter NAL unit
• h264Splitter4 for 0001 header starter NAL unit

This has been coded to run under Linux. (tested on pop-os!)

I recommend you to use a binary reader such as xxd. Open a terminal and type the following

xxd <you_h264_file> | head -n 3

this will give you a result like this:

00000000: 0000 0001 6742 c01f da03 204d f961 0000  ....gB.... M.a..
00000010: 0300 0100 0003 003c 8f18 32a0 0000 0001  .......<..2.....
00000020: 68ce 32c8 0000 0106 05ff ff62 dc45 e9bd  h.2........b.E..

The important part is the first line

00000000: 0000 0001 6742 c01f da03 204d f961 0000  ....gB.... M.a..

we can conclude that this file uses a 0001 header starter, because it has 0000 0001 at the beginning. On the other hand, if your file has the following at the first line:

00000000: 0000 0167 42c0 1fda 0320 4df9 61000003  ...gB.... M.a...

your file has a 001 header starter.

I recomend you to use a binary reader and check the first line

Remember that mp4 is a container and not a codec, so you have to use ffmpeg. Try this:

ffmpeg -i <your_file_name>.mp4 -an -vcodec libx264 -crf 23 <your_output_file_name>.h264

For running the splitter

./h264Splitter4 <your_h264_file>

this will generate one file per each NAL unit contained in your h264 file, it will start at 0 until the last NAL unit, like this:

<your_h264_file>.0000
<your_h264_file>.0001
<your_h264_file>.0003
.
.
.
<your_h264_file>.<last_NAL_unit>

Remember that NAL units can be interpreted as "frames"

• Exploring H.264. Part 2: H.264 Bitstream format

• Introduction to H.264: (1) NAL Unit