[Ffmpeg-devel] Problem with output_example (3gp files)

Mantenna mantenna
Mon Mar 20 18:53:46 CET 2006


I have a problem with output_example on linux redhat 9
and FFMPEG-CVS (180306).

I have tried to generate a file.3gp with this video
stream settings:

	/* put sample parameters */
	c->bit_rate = 30000;
    	/* resolution must be a multiple of two */
    	c->width = 176;
    	c->height = 144;

and this audio settings:

	/* put sample parameters */
    	c->bit_rate = 8000;
    	c->sample_rate = 11025;
    	c->channels = 1;

For my special case, i have changed the default audio
enconder (AMR) with AAC
in file libavformat/movenc.c


	static AVOutputFormat _3gp_oformat = {
		"3gp format",
		//original  CODEC_ID_AMR_NB,
	    	.flags = AVFMT_GLOBALHEADER,


The output file.3gp is readable from VLC player, not
with QuickTime player 7.0 (an -50 unspecified error),
but not some mobile phone as Motorola A835(video is ok
but no sound).

I'm sure that this mobile phone is to able to read and
play this special file format (H263+AAC)
because i've created a test file.3gp with ffmpeg:

ffmpeg -i Xlab2.mov -s 176x144 output.3gp

and it plays correctly.

Is there any initialization missing for the AAC codec
to open it?

Thanks in advance for any help

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