mad-dev June 2007

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mad_stream_skip to seek to a new frame
by www.bigcab＠free.fr 19 Jun '07

19 Jun '07

I think I can use mad_stream_skip to seek a new frame but I always got a lost sync error I don't understand?

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libmad know the current bytes read or decoded
by www.bigcab＠free.fr 18 Jun '07

18 Jun '07

here I would like to know if it could be possible to know if we could retrive the current byte read (an equivalent of ftell) aren't there any functions for it? thanks very much

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problem with the seeking
by www.bigcab＠free.fr 18 Jun '07

18 Jun '07

Hi here I've got a VBR (variable bitrate file ) so I can't seek the right frame It's not as if I had a Pcm file can someone help me?

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libid3tag
by cab 16 Jun '07

16 Jun '07

Hello, Ok I'm here to report a few bugs with libid3tag The function id3_file_open works half the time file=id3_file_open(input,ID3_FILE_MODE_READONLY); if (file==NULL) { printf("file error(id3_tag_size fun)\n"); return 1; } this line often return 1 and prints file error each time I execute this command, I check the file path and it's correct so I concluded that the bug was coming from this function. Thanks. Best Regards Cab

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seeking error
by www.bigcab＠free.fr 08 Jun '07

08 Jun '07

rob wrote : Sadeesh Kumar wrote: > In libmad, when the song is playing, how can i jump to different > differnt location and start to play from that location?. I find it, there is > no direct easy interface to do this. To jump to a new location using the low-level API: 1. Seek to an approximate location in the file and load your buffer with data from the new position. 2. Call mad_stream_buffer() to update the stream pointers for the modified buffer. 3. Call mad_frame_mute() and mad_synth_mute(). At this point you can simply resume decoding. However, to avoid any unpleasant burps in the audio, unless you have seeked to the very beginning of the file, it is best to: 4. Call mad_frame_decode() successfully at least twice. Note that the first few calls will probably yield recoverable decoding errors which you can safely ignore. 5. Call mad_synth_frame() once and discard the resulting PCM. The MAD plug-in for Winamp does all of this if you're looking for an example. Cheers, -rob but the problem is I've got these errors decoding error 0x0101 (lost synchronization) at byte offset 4096 decoding error 0x0235 (bad main_data_begin pointer) at byte offset 4203 and then my player doesn't work any more, there's a bug what is wrong ? here my source code int seek(state*status /*structure to store the data*/,int value) { printf("seeking in mp3 started\n"); struct mad_stream *stream; stream=status->stream; struct mad_frame frame; frame=status->mad_frame; struct mad_synth synth; synth=status->synth; printf("%lf is the value in percent\n",value); pthread_mutex_lock(&mutex); int seek_bit; int bitrate=status->bitrate; int samplerate=status->srate; int frame_size=144*bitrate/samplerate; seek_bit=percent_to_bits(status->mp3_file_size,(int)value); int reste=seek_bit-status->cur_bit; int factor=reste/frame_size; seek_bit=status->cur_bit+factor*frame_size+4*factor; printf("mad stream buffer call\n"); mad_stream_buffer(stream,status->start_mp3+seek_bit,status->mp3_file_size-seek_bit); status->cur_bit=seek_bit; mad_frame_mute(&frame); mad_synth_mute(&synth); int result,i=0; result=mad_frame_decode(&frame,stream); while((result!=0)||(i<2)) { result=mad_frame_decode(&frame,stream); i+=1; } mad_synth_frame(&synth,&frame); pthread_mutex_unlock(&mutex); printf("seeking in mp3 ended\n"); return 0; } what is wrong with my source code?

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mad-dev June 2007