MP4 Containers created by MP4Box fail to parse having 'meta' atom set

[jotzet79]

Hello there,

I have issues when I'm trying to convert Original Sony ILCE-7M4 movies to HEVC with a lower bitrate, and adding a META box / atom via MP4Box.
I do the following steps:

First I CONVert the ORIGinal File
ffmpeg -i "${ORIGFILE}" -preset faster -c:v libx265 -crf 17 -c:a aac_at -b:a 192k -movflags use_metadata_tags+faststart -map_metadata 0 -tag:v hvc1 "${CONVFILE}"

Then I add a meta box to a new PROCessed file (previously I added XML data to the meta, but this does not make any difference)
MP4Box -add "${CONVFILE}#1" -add "${CONVFILE}#2" -set-meta meta:tk=1 -new "${PROCFILE}"

When I then try to parse the file via mp4parse::read_mp4(&mut file).unwrap() I get thread 'main' panicked at 'called Result::unwrap()on anErr value: InvalidData(CheckParserStateErr)'

Can you please have a look at this? In the gpac area I already tried to investigate what happens, but I have to confess that I'm not an expert obviously ;). -> gpac/gpac#2603

Thank you very much,
Joachim

[kelvie]

I'm also trying to get this workflow working (in my case, I want to compress the audio coming out of my Sony camera to aac, as uncompressed it is about half the video size and takes forever for google photos to process, and then potentially run gyroflow on the result after).

Did you figure out how to import a MP4Box-modified mp4 into gyroflow @jotzet79 ? Or did figure out a way to add the data using a different tool?

[kelvie]

It appears that this is only triggered when enabling the "meta-xml" feature flag. Not enabling it makes this parse fine.

[cbrl]

I just encountered this exact issue trying to use Gyroflow on a transcoded video. As @kelvie mentioned, some part of the code enabled by the meta-xml feature is causing this issue.

For Gyroflow specifically, the problem is happening in the https://github.com/AdrianEddy/telemetry-parser dependency. However, that project has removed the use of the meta-xml feature as of a few days ago: AdrianEddy/telemetry-parser@21eddb1. Whenever that change makes its way downstream, Gyroflow should at least work for this case. However, the source of the issue in this project still remains.

[jotzet79]

Hi @kelvie & @cbrl,

Sorry for the delay, had to dig into my project again...

In the end I tried a combination of different MP4 Container Manipulation tools, and in the following snippet I try different CRFs and PRS params for pixel peeping... ;-)

#!/bin/bash
ORIGFILE="${1}"
CUTOFF=FULL
CONVFILE="${ORIGFILE}-${CUTOFF}.CONV.MP4"
TEMPFILE="${ORIGFILE}-${CUTOFF}.TEMP.MP4"
PROCFILE="${ORIGFILE}-${CUTOFF}.PROC.MP4"
METAFILE="${ORIGFILE}.META.XML"

for CRF in 15 16 17 18 19 20 21 22 23 24 25 26 27 28;
do
	for PRS in 03-slow 04-medium 05-fast 06-faster;
	do
		# Convert the ORIGinal file to H265 CONVerted file
		echo "Conversion Params ${CONVFILE}_CRF-${CRF}_PRS-${PRS}.MP4" 

		CONVFILE0="${CONVFILE}"
		PROCFILE0="${PROCFILE}"

		CONVFILE="${CONVFILE}_CRF-${CRF}_PRS-${PRS}.MP4"
		PROCFILE="${PROCFILE}_CRF-${CRF}_PRS-${PRS}.MP4"

		ffmpeg -i "${ORIGFILE}" -c:v libx265 -crf "$CRF" -preset "${PRS:3}" -profile:v main422-10 -x265-params "level-idc=51:high-tier=1" -c:a aac_at -b:a 320k -movflags use_metadata_tags+faststart -map_metadata 0 -tag:v hvc1 "${CONVFILE}"

		# Add existing rtmd data track from the ORIGinal file add it to the CONVerted file
		MP4Box -bo -brand XAVC:16785407 -ab XAVC -ab mp42 -ab iso2 -ab nras -rb isom -rb mp41 -add "${ORIGFILE}#3" "${CONVFILE}"

		# Extract 'meta' box from original file
		/usr/local/Cellar/bento4/1.6.0-640/bin/mp4extract "meta" "$ORIGFILE" "${METAFILE}"

		# Create new processed file and add the 'meta' box data from the META-File
		/usr/local/Cellar/bento4/1.6.0-640/bin/mp4edit --insert :"${METAFILE}" "${CONVFILE}" "$PROCFILE"

		# Do whatever with the files like renaming...
		CONVFILE="${CONVFILE0}"
		PROCFILE="${PROCFILE0}"

	done
done