[Libav-user] warning of "[libmp3lame @ 00CAB020] frame_size is too large" while calling avcodec_encode_audio2()

[zhao0130 at umn.edu]

I am using ffmpeg api to transcode a movie (.mp4 -> .mov). I got a warning 
while calling avcodec_encode_audio2(): "[libmp3lame @ 00CAB020] frame_size 
is too large". I believe this should be due to that the frame size of 
decoding AVCodecContext, 1024, is different from that of encoding 
AVCodecContext, 1152. The audio codec of the mp4 file is AAC and that of 
the mov file is MP3. The default of frame size of MP3 seems 1152 and I can 
not force it to be 1024. I set other parameters such as sample_rate, 
bit_rate, sample_fmt and channels of encoding AVCodecContext same as those 
of decoding AVCodecContext. Help will be really appreciated!