[M4IF Technotes] generation of mp4 files

[Ivan Dimkovic]

Dear Xin, All
1. (Actually, guys from MPEG4IP project would probably give more precise
answer):  MPEG4IP has several decoders - Xvid decoder used for Simple
profile, and ISO reference decoder (Microsoft) for all other profiles,
because (to my best knowledge) Xvid decoder does not support other profiles
than simple (and maybe advanced simple).  Xvid decoder is used for simple
profile because it is much faster than unoptimized ISO reference source
code.
Xvid encoder should generate ISO compatible elementary bitstreams   (simple
profile,  or in SigmaDesign's derrivate  even Advanced Simple).
To my best knowledge, QT Pro MPEG-4 video codec is ISO compliant.
2.  QT6 won't recognize .aac (elementary stream audio) file,  it can only
read MP4 file format - so you must multiplex MPEG-4 Low Complexity AAC file
into .mp4.    As far as I know,  FAAC generates ISO/MPEG-4 compliant files -
make sure that you are using "MPEG-4 AAC" and not "MPEG-2 AAC" in FAAC,
because some decoders won't play MP4 files with 'MPEG-2 AAC' object type
inside.
Best regards / Mit freundlichen Gru?en
Ivan Dimkovic
----------------------------------------------------------------
Ivan Dimkovic
MPEG-4 Software R&D
Ahead Software AG     phone: +49 (0)7248 911 822(direct line)
Im Stoeckmaedle 18    fax:   +49 (0)7248 911 888
76307 Karlsbad        email: idimkovic   nero.com
Germany               web:    www.nero.com
----------------------------------------------------------------
-----Original Message-----
From: technotes-admin   lists.m4if.org
[mailto:technotes-admin   lists.m4if.org]On Behalf Of xin chen
Sent: Friday, October 04, 2023 10:10 AM
To: technotes   lists.m4if.org
Subject: [M4IF Technotes] generation of mp4 files
Hi all,
I've some questions during generation a mp4 file:
1.Video Encoder: when player of mpeg4ip (gmp4player)
is used to decode the mp4 file generated by QT Pro, it
reports to use xvid plug-in to decode video, while
mpeg4ip itself supplies two kinds of encoder: ISO
encoder(mp4venc) and xvid encoder(xvidenc). So xvid is
different from ISO encoder, but it's ISO compliant?
Who can give me a detailed explanation of QT Pro
Encoder and its compliance with ISO?
2. Audio Encoder: I tried different ways to encode a
wav file to AAC format, under windows .aac is
generated but it is not recognized by QT, and when
.aac is packaged to .mp4 by mpeg4ip, cannot decoded by
QT either. Under Linux, I use the FAAC from mpeg4ip,
it fails and says:
faac -pLOW -b128 true.wav
Without libsndfile, only raw format is allowed
What does it mean? I think the wav file is correct
because it can be encoded into mp3 by lame of mpeg4ip.
Thank you very much.
__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com
_______________________________________________
Technotes mailing list
Technotes   lists.m4if.org
http://lists.m4if.org/mailman/listinfo/technotes