[FFmpeg-user] Concatenating two MPEG4 AAC movies fails with "invalid, clipping"

[Nikolas Borrel-Jensen]

Hi

I’m concatenating two AAC encoded movies in a mp4 container as

ffmpeg -f concat -i /concat_scripts -c:a copy -c:v copy output.mp4

but I get a bunch of error messages like

[mp4 @ 0x7fbc61821400] st:0 PTS: 5433 DTS: 5412 < 35774 invalid, clipping
[concat @ 0x7fbc61801200] Invalid stream index 1
[mp4 @ 0x7fbc61821400] st:0 PTS: 5453 DTS: 5432 < 35775 invalid, clipping

If I concatenate the same movie twice it works, and also if I convert both movies with 

ffmpeg -i my_movie.mp4 -qscale 0 -r 24.028 -y -acodec copy my_movie.mp4

it works when the two movies are concatenated. 

I’m fine with converting the intro movie but not the user-generated one, since it is time-consuming. 

The movie files can be found here:  https://www.dropbox.com/sh/mg8pce1vnenucra/AADPWr52jF6vIVyKq9AdcVP4a?dl=0 <https://www.dropbox.com/sh/mg8pce1vnenucra/AADPWr52jF6vIVyKq9AdcVP4a?dl=0>

Below is the output from exiftool (formatted as x / y, where x denotes the values for the static movie and y the values for the user-generated movie recorded using iOS’ AVAssetWriter). Thanks in advance.

ExifTool Version Number		: 9.96 / 9.96
File Name				: intro_animation.mp4 / user_generated_movie.mp4
Directory					: .
File Size					: 24 kB / 1701 kB
File Type					: MP4 / MP4 
File Type Extension			: mp4 / mp4
MIME Type				: video/mp4 / video/mp4
Major Brand				: MP4  Base Media v1 [IS0 14496-12:2003] / MP4 v2 [ISO 14496-14]
Minor Version				: 0.2.0 / 0.0.1
Compatible Brands			: isom, iso2, avc1, mp41 / mp41, mp42, isom
Movie Data Size			: 23168 / 1735041
Movie Data Offset			: 48 / 44
Movie Header Version		: 0 / 0
Time Scale				: 1000 / 1000
Duration					: 3.07 s / 9.82 s
Preferred Rate			: 1 / 1
Preferred Volume			: 100.00% / 100.00% 
Preview Time				: 0 s / 0 s
Preview Duration			: 0 s / 0 s
Poster Time				: 0 s / 0 s
Selection Time			: 0 s / 0 s
Selection Duration			: 0 s / 0 s
Current Time				: 0 s / 0 s
Next Track ID				: 2 / 3
Track Header Version		: 0 / 0
Track ID					: 1 / 1
Track Duration				: 3.07 s / 9.82 s
Track Layer				: 0 / 0
Track Volume				: 0.00% / 0.00%
Matrix Structure			: 1 0 0 0 1 0 0 0 1 / 1 0 0 0 1 0 0 0 1
Image Width				: 960 / 960
Image Height				: 540 / 540
Media Header Version		: 0 / 0
Media Time Scale			: 11988 / 44100
Media Duration			: 3.07 s / 9.91 s
Media Language Code		: eng / und
Handler Description		: VideoHandler / Core Media Audio
Graphics Mode			: srcCopy / srcCopy
Op Color					: 0 0 0 / 0 0 0
Compressor ID			: avc1 / avc1
Source Image Width		: 960 / 960
Source Image Height		: 540 / 540
X Resolution				: 72 / 72
Y Resolution				: 72 / 72
Bit Depth					: 24 / 24
Video Frame Rate			: 29.97 / 29.97
Handler Type				: Metadata / Audio Track
Handler Vendor ID			: Apple / [not present]
Encoder					: Lavf54.63.104 / [not present]
Avg Bitrate				: 60.4 kbps / 1.41 Mbps
Image Size				: 960x540 / 960x540
Megapixels				: 0.518 / 0.518
Rotation					: 0 / 0