diff options
Diffstat (limited to 'examples/decoder_example.c')
| -rw-r--r-- | examples/decoder_example.c | 66 |
1 files changed, 33 insertions, 33 deletions
diff --git a/examples/decoder_example.c b/examples/decoder_example.c index 90ea63d1..e264e403 100644 --- a/examples/decoder_example.c +++ b/examples/decoder_example.c @@ -74,7 +74,7 @@ int main(){ /********** Decode setup ************/ ogg_sync_init(&oy); /* Now we can read pages */ - + while(1){ /* we repeat if the bitstream is chained */ int eos=0; int i; @@ -88,60 +88,60 @@ int main(){ buffer=ogg_sync_buffer(&oy,4096); bytes=fread(buffer,1,4096,stdin); ogg_sync_wrote(&oy,bytes); - + /* Get the first page. */ if(ogg_sync_pageout(&oy,&og)!=1){ /* have we simply run out of data? If so, we're done. */ if(bytes<4096)break; - + /* error case. Must not be Vorbis data */ fprintf(stderr,"Input does not appear to be an Ogg bitstream.\n"); exit(1); } - + /* Get the serial number and set up the rest of decode. */ /* serialno first; use it to set up a logical stream */ ogg_stream_init(&os,ogg_page_serialno(&og)); - + /* extract the initial header from the first page and verify that the Ogg bitstream is in fact Vorbis data */ - + /* I handle the initial header first instead of just having the code read all three Vorbis headers at once because reading the initial header is an easy way to identify a Vorbis bitstream and it's useful to see that functionality seperated out. */ - + vorbis_info_init(&vi); vorbis_comment_init(&vc); - if(ogg_stream_pagein(&os,&og)<0){ + if(ogg_stream_pagein(&os,&og)<0){ /* error; stream version mismatch perhaps */ fprintf(stderr,"Error reading first page of Ogg bitstream data.\n"); exit(1); } - - if(ogg_stream_packetout(&os,&op)!=1){ + + if(ogg_stream_packetout(&os,&op)!=1){ /* no page? must not be vorbis */ fprintf(stderr,"Error reading initial header packet.\n"); exit(1); } - - if(vorbis_synthesis_headerin(&vi,&vc,&op)<0){ + + if(vorbis_synthesis_headerin(&vi,&vc,&op)<0){ /* error case; not a vorbis header */ fprintf(stderr,"This Ogg bitstream does not contain Vorbis " "audio data.\n"); exit(1); } - + /* At this point, we're sure we're Vorbis. We've set up the logical (Ogg) bitstream decoder. Get the comment and codebook headers and set up the Vorbis decoder */ - + /* The next two packets in order are the comment and codebook headers. They're likely large and may span multiple pages. Thus we read and submit data until we get our two packets, watching that no pages are missing. If a page is missing, error out; losing a header page is the only place where missing data is fatal. */ - + i=0; while(i<2){ while(i<2){ @@ -180,7 +180,7 @@ int main(){ } ogg_sync_wrote(&oy,bytes); } - + /* Throw the comments plus a few lines about the bitstream we're decoding */ { @@ -192,7 +192,7 @@ int main(){ fprintf(stderr,"\nBitstream is %d channel, %ldHz\n",vi.channels,vi.rate); fprintf(stderr,"Encoded by: %s\n\n",vc.vendor); } - + convsize=4096/vi.channels; /* OK, got and parsed all three headers. Initialize the Vorbis @@ -203,7 +203,7 @@ int main(){ proceed in parallel. We could init multiple vorbis_block structures for vd here */ - + /* The rest is just a straight decode loop until end of stream */ while(!eos){ while(!eos){ @@ -217,7 +217,7 @@ int main(){ this point */ while(1){ result=ogg_stream_packetout(&os,&op); - + if(result==0)break; /* need more data */ if(result<0){ /* missing or corrupt data at this page position */ /* no reason to complain; already complained above */ @@ -225,21 +225,21 @@ int main(){ /* we have a packet. Decode it */ float **pcm; int samples; - + if(vorbis_synthesis(&vb,&op)==0) /* test for success! */ vorbis_synthesis_blockin(&vd,&vb); - /* - + /* + **pcm is a multichannel float vector. In stereo, for example, pcm[0] is left, and pcm[1] is right. samples is the size of each channel. Convert the float values (-1.<=range<=1.) to whatever PCM format and write it out */ - + while((samples=vorbis_synthesis_pcmout(&vd,&pcm))>0){ int j; int clipflag=0; int bout=(samples<convsize?samples:convsize); - + /* convert floats to 16 bit signed ints (host order) and interleave */ for(i=0;i<vi.channels;i++){ @@ -264,17 +264,17 @@ int main(){ ptr+=vi.channels; } } - + if(clipflag) fprintf(stderr,"Clipping in frame %ld\n",(long)(vd.sequence)); - - + + fwrite(convbuffer,2*vi.channels,bout,stdout); - + vorbis_synthesis_read(&vd,bout); /* tell libvorbis how many samples we actually consumed */ - } + } } } if(ogg_page_eos(&og))eos=1; @@ -287,10 +287,10 @@ int main(){ if(bytes==0)eos=1; } } - + /* ogg_page and ogg_packet structs always point to storage in libvorbis. They're never freed or manipulated directly */ - + vorbis_block_clear(&vb); vorbis_dsp_clear(&vd); }else{ @@ -299,7 +299,7 @@ int main(){ /* clean up this logical bitstream; before exit we see if we're followed by another [chained] */ - + ogg_stream_clear(&os); vorbis_comment_clear(&vc); vorbis_info_clear(&vi); /* must be called last */ @@ -307,7 +307,7 @@ int main(){ /* OK, clean up the framer */ ogg_sync_clear(&oy); - + fprintf(stderr,"Done.\n"); return(0); } |