"Convert" might create bogus MP3 files
I converted several MP4/FLV videos using the "Open Multiple Files..." -> "Convert" feature by using the shipped "Audio - MP3" profile. After converting a few files I recognized the bitrate was just 128 kb/s, so I changed to to 160 kb/s.
Later on when I tried to play those 160 kb/s files on my car radio they didn't work. It seemed to be able to open them, but just didn't play them. The time was stuck at 0:00. The 128 kb/s ones are fine.
I also tested this with some other hardware devices e.g. portable MP3 player and they all showed the same behavior.
VLC/MPC-HC (with K-Lite Mega Codec Pack installed) are able to play those files without any problems.
I checked the files using the "Checkmate MP3 Checker" version 0.19 and it shows the 128 kb/s ones as OK adn the 160 kb/s ones as broken. The data it shows for the files seems to be okay, but what stand out is, that the 160 kb/s ones are VBR with varying bitranges and have a random layer version (ranges from 1 to 3) and the 128 kb/s ones all have the proper layer version 3 and are CBR. It seems like is something is wrong with the header of those 160 kb/s files.
The command-line version of the checker shows better information:
working version MPEG v1.0 layer 3 bitrate 128000 bps samplerate 44100 Hz frames 70183 time 30:33.351 unidentified 0 b (0%) stereo yes size 28646 KiB ID3V1 no ID3V2 no last frame offset 29333211 b (0x1bf96db) length 418 errors none result Ok
broken version MPEG v1.0 layer 2 average bitrate 157412 bps (VBR) samplerate 44100 Hz frames 28086 time 12:13.675 unidentified 4478562 b (20%) errors unidentified bytes inconsistent frame headers invalid header values CRC error result Bad
In the verbose mode it also shows lots of "unknown bitrate" and "layer differs from previous frame" message.
Interestingly there isn't even a CBR/VBR selection in the conversion dialog, so I would assume it should always be CBR.
I also tried the tool "MP3 Diags" version 1.2.01, which goes into even more detail. I attached the information it shows - unfortunately as an image since I have having trouble to copy and paste the information out of the application.