Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: padding aac frames / fill element (Read 5898 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

padding aac frames / fill element

hi,
I am trying to create a mp4 file with an aac audio stream.
I need to have constant sized samples. it is from a live stream. mp4 format forces me to either have constant size or predict size of each frame.
I tried to add padding to each aac frame using a fill element but vlc can't read it correctely (sound is distorted) and it says :
...
[00000446] faad decoder warning: PCE shall be the first element in a frame
[00000446] faad decoder warning: PCE shall be the first element in a frame
[00000446] faad decoder warning: PCE shall be the first element in a frame
...

this is a sample result file : http://dl.free.fr/vFYOpT7JK

can somebody give me some hints ?
thanks for your help.

padding aac frames / fill element

Reply #1 –
You put the fill element right after each frame? That is wrong, you need to put it before the ID_END marker, otherwise it will indeed be the first element of the next frame.

padding aac frames / fill element

Reply #2 –
Quote from: menno on
You put the fill element right after each frame? That is wrong, you need to put it before the ID_END marker, otherwise it will indeed be the first element of the next frame.

oops...  seems logical to put it before id_end. 
I will try it. thanks.

padding aac frames / fill element

Reply #3 –
Quote from: menno on
You put the fill element right after each frame? That is wrong, you need to put it before the ID_END marker, otherwise it will indeed be the first element of the next frame.


you were right. thank you menno!

padding aac frames / fill element

Reply #4 –
hi,
I have some issues on the aac stream to find the ID_END. the aac frames are not aligned with 0 which means I can't just take the 3 last bits set to 1.
I can't find any other solution than entirely parsing the aac stream to find the ID_END. If you have any alternative solution, I will take it.
thanks for your help.