diff options
Diffstat (limited to 'lib/vorbisfile.c')
| -rw-r--r-- | lib/vorbisfile.c | 1156 |
1 files changed, 1156 insertions, 0 deletions
diff --git a/lib/vorbisfile.c b/lib/vorbisfile.c new file mode 100644 index 00000000..eb49fc80 --- /dev/null +++ b/lib/vorbisfile.c @@ -0,0 +1,1156 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. * + * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY * + * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. * + * PLEASE READ THESE TERMS DISTRIBUTING. * + * * + * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000 * + * by Monty <monty@xiph.org> and The XIPHOPHORUS Company * + * http://www.xiph.org/ * + * * + ******************************************************************** + + function: stdio-based convenience library for opening/seeking/decoding + last mod: $Id: vorbisfile.c,v 1.25.4.1 2000/08/15 08:33:46 xiphmont Exp $ + + ********************************************************************/ + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <math.h> +#include <assert.h> + +#include "vorbis/codec.h" +#include "vorbis/vorbisfile.h" + +#include "os.h" +#include "misc.h" + +/* A 'chained bitstream' is a Vorbis bitstream that contains more than + one logical bitstream arranged end to end (the only form of Ogg + multiplexing allowed in a Vorbis bitstream; grouping [parallel + multiplexing] is not allowed in Vorbis) */ + +/* A Vorbis file can be played beginning to end (streamed) without + worrying ahead of time about chaining (see decoder_example.c). If + we have the whole file, however, and want random access + (seeking/scrubbing) or desire to know the total length/time of a + file, we need to account for the possibility of chaining. */ + +/* We can handle things a number of ways; we can determine the entire + bitstream structure right off the bat, or find pieces on demand. + This example determines and caches structure for the entire + bitstream, but builds a virtual decoder on the fly when moving + between links in the chain. */ + +/* There are also different ways to implement seeking. Enough + information exists in an Ogg bitstream to seek to + sample-granularity positions in the output. Or, one can seek by + picking some portion of the stream roughly in the desired area if + we only want course navigation through the stream. */ + +/************************************************************************* + * Many, many internal helpers. The intention is not to be confusing; + * rampant duplication and monolithic function implementation would be + * harder to understand anyway. The high level functions are last. Begin + * grokking near the end of the file */ + +/* read a little more data from the file/pipe into the ogg_sync framer */ +#define CHUNKSIZE 4096 +static long _get_data(OggVorbis_File *vf){ + char *buffer=ogg_sync_buffer(&vf->oy,CHUNKSIZE); + long bytes=(vf->callbacks.read_func)(buffer,1,CHUNKSIZE,vf->datasource); + ogg_sync_wrote(&vf->oy,bytes); + return(bytes); +} + +/* save a tiny smidge of verbosity to make the code more readable */ +static void _seek_helper(OggVorbis_File *vf,long offset){ + (vf->callbacks.seek_func)(vf->datasource, offset, SEEK_SET); + vf->offset=offset; + ogg_sync_reset(&vf->oy); +} + +/* The read/seek functions track absolute position within the stream */ + +/* from the head of the stream, get the next page. boundary specifies + if the function is allowed to fetch more data from the stream (and + how much) or only use internally buffered data. + + boundary: -1) unbounded search + 0) read no additional data; use cached only + n) search for a new page beginning for n bytes + + return: -1) did not find a page + n) found a page at absolute offset n */ + +static long _get_next_page(OggVorbis_File *vf,ogg_page *og,int boundary){ + if(boundary>0)boundary+=vf->offset; + while(1){ + long more; + + if(boundary>0 && vf->offset>=boundary)return(-1); + more=ogg_sync_pageseek(&vf->oy,og); + + if(more<0){ + /* skipped n bytes */ + vf->offset-=more; + }else{ + if(more==0){ + /* send more paramedics */ + if(!boundary)return(-1); + if(_get_data(vf)<=0)return(-1); + }else{ + /* got a page. Return the offset at the page beginning, + advance the internal offset past the page end */ + long ret=vf->offset; + vf->offset+=more; + return(ret); + + } + } + } +} + +/* find the latest page beginning before the current stream cursor + position. Much dirtier than the above as Ogg doesn't have any + backward search linkage. no 'readp' as it will certainly have to + read. */ +static long _get_prev_page(OggVorbis_File *vf,ogg_page *og){ + long begin=vf->offset; + long ret; + int offset=-1; + + while(offset==-1){ + begin-=CHUNKSIZE; + _seek_helper(vf,begin); + while(vf->offset<begin+CHUNKSIZE){ + ret=_get_next_page(vf,og,begin+CHUNKSIZE-vf->offset); + if(ret==-1){ + break; + }else{ + offset=ret; + } + } + } + + /* we have the offset. Actually snork and hold the page now */ + _seek_helper(vf,offset); + ret=_get_next_page(vf,og,CHUNKSIZE); + if(ret==-1){ + /* this shouldn't be possible */ + fprintf(stderr,"Missed page fencepost at end of logical bitstream. " + "Exiting.\n"); + exit(1); + } + return(offset); +} + +/* finds each bitstream link one at a time using a bisection search + (has to begin by knowing the offset of the lb's initial page). + Recurses for each link so it can alloc the link storage after + finding them all, then unroll and fill the cache at the same time */ +static void _bisect_forward_serialno(OggVorbis_File *vf, + long begin, + long searched, + long end, + long currentno, + long m){ + long endsearched=end; + long next=end; + ogg_page og; + long ret; + + /* the below guards against garbage seperating the last and + first pages of two links. */ + while(searched<endsearched){ + long bisect; + + if(endsearched-searched<CHUNKSIZE){ + bisect=searched; + }else{ + bisect=(searched+endsearched)/2; + } + + _seek_helper(vf,bisect); + ret=_get_next_page(vf,&og,-1); + if(ret<0 || ogg_page_serialno(&og)!=currentno){ + endsearched=bisect; + if(ret>=0)next=ret; + }else{ + searched=ret+og.header_len+og.body_len; + } + } + + _seek_helper(vf,next); + ret=_get_next_page(vf,&og,-1); + + if(searched>=end || ret==-1){ + vf->links=m+1; + vf->offsets=malloc((m+2)*sizeof(int64_t)); + vf->offsets[m+1]=searched; + }else{ + _bisect_forward_serialno(vf,next,vf->offset, + end,ogg_page_serialno(&og),m+1); + } + + vf->offsets[m]=begin; +} + +/* uses the local ogg_stream storage in vf; this is important for + non-streaming input sources */ +static int _fetch_headers(OggVorbis_File *vf,vorbis_info *vi,vorbis_comment *vc, + long *serialno){ + ogg_page og; + ogg_packet op; + int i,ret; + + ret=_get_next_page(vf,&og,CHUNKSIZE); + if(ret==-1){ + fprintf(stderr,"Did not find initial header for bitstream.\n"); + return -1; + } + + if(serialno)*serialno=ogg_page_serialno(&og); + ogg_stream_init(&vf->os,ogg_page_serialno(&og)); + + /* extract the initial header from the first page and verify that the + Ogg bitstream is in fact Vorbis data */ + + vorbis_info_init(vi); + vorbis_comment_init(vc); + + i=0; + while(i<3){ + ogg_stream_pagein(&vf->os,&og); + while(i<3){ + int result=ogg_stream_packetout(&vf->os,&op); + if(result==0)break; + if(result==-1){ + fprintf(stderr,"Corrupt header in logical bitstream.\n"); + goto bail_header; + } + if(vorbis_synthesis_headerin(vi,vc,&op)){ + fprintf(stderr,"Illegal header in logical bitstream.\n"); + goto bail_header; + } + i++; + } + if(i<3) + if(_get_next_page(vf,&og,1)<0){ + fprintf(stderr,"Missing header in logical bitstream.\n"); + goto bail_header; + } + } + return 0; + + bail_header: + vorbis_info_clear(vi); + vorbis_comment_clear(vc); + ogg_stream_clear(&vf->os); + return -1; +} + +/* last step of the OggVorbis_File initialization; get all the + vorbis_info structs and PCM positions. Only called by the seekable + initialization (local stream storage is hacked slightly; pay + attention to how that's done) */ +static void _prefetch_all_headers(OggVorbis_File *vf,vorbis_info *first_i, + vorbis_comment *first_c, + long dataoffset){ + ogg_page og; + int i,ret; + + vf->vi=calloc(vf->links,sizeof(vorbis_info)); + vf->vc=calloc(vf->links,sizeof(vorbis_info)); + vf->dataoffsets=malloc(vf->links*sizeof(int64_t)); + vf->pcmlengths=malloc(vf->links*sizeof(int64_t)); + vf->serialnos=malloc(vf->links*sizeof(long)); + + for(i=0;i<vf->links;i++){ + if(first_i && first_c && i==0){ + /* we already grabbed the initial header earlier. This just + saves the waste of grabbing it again */ + memcpy(vf->vi+i,first_i,sizeof(vorbis_info)); + memcpy(vf->vc+i,first_c,sizeof(vorbis_comment)); + vf->dataoffsets[i]=dataoffset; + }else{ + + /* seek to the location of the initial header */ + + _seek_helper(vf,vf->offsets[i]); + if(_fetch_headers(vf,vf->vi+i,vf->vc+i,NULL)==-1){ + fprintf(stderr,"Error opening logical bitstream #%d.\n\n",i+1); + vf->dataoffsets[i]=-1; + }else{ + vf->dataoffsets[i]=vf->offset; + ogg_stream_clear(&vf->os); + } + } + + /* get the serial number and PCM length of this link. To do this, + get the last page of the stream */ + { + long end=vf->offsets[i+1]; + _seek_helper(vf,end); + + while(1){ + ret=_get_prev_page(vf,&og); + if(ret==-1){ + /* this should not be possible */ + fprintf(stderr,"Could not find last page of logical " + "bitstream #%d\n\n",i); + vorbis_info_clear(vf->vi+i); + vorbis_comment_clear(vf->vc+i); + break; + } + if(ogg_page_frameno(&og)!=-1){ + vf->serialnos[i]=ogg_page_serialno(&og); + vf->pcmlengths[i]=ogg_page_frameno(&og); + break; + } + } + } + } +} + +static int _make_decode_ready(OggVorbis_File *vf){ + if(vf->decode_ready)exit(1); + vorbis_synthesis_init(&vf->vd,vf->vi); + vorbis_block_init(&vf->vd,&vf->vb); + vf->decode_ready=1; + return(0); +} + +static int _open_seekable(OggVorbis_File *vf){ + vorbis_info initial_i; + vorbis_comment initial_c; + long serialno,end; + int ret; + long dataoffset; + ogg_page og; + + /* is this even vorbis...? */ + ret=_fetch_headers(vf,&initial_i,&initial_c,&serialno); + dataoffset=vf->offset; + ogg_stream_clear(&vf->os); + if(ret==-1)return(-1); + + /* we can seek, so set out learning all about this file */ + vf->seekable=1; + (vf->callbacks.seek_func)(vf->datasource,0,SEEK_END); + vf->offset=vf->end=(vf->callbacks.tell_func)(vf->datasource); + + /* We get the offset for the last page of the physical bitstream. + Most OggVorbis files will contain a single logical bitstream */ + end=_get_prev_page(vf,&og); + + /* moer than one logical bitstream? */ + if(ogg_page_serialno(&og)!=serialno){ + + /* Chained bitstream. Bisect-search each logical bitstream + section. Do so based on serial number only */ + _bisect_forward_serialno(vf,0,0,end+1,serialno,0); + + }else{ + + /* Only one logical bitstream */ + _bisect_forward_serialno(vf,0,end,end+1,serialno,0); + + } + + _prefetch_all_headers(vf,&initial_i,&initial_c,dataoffset); + return(ov_raw_seek(vf,0)); + +} + +static int _open_nonseekable(OggVorbis_File *vf){ + /* we cannot seek. Set up a 'single' (current) logical bitstream entry */ + vf->links=1; + vf->vi=calloc(vf->links,sizeof(vorbis_info)); + vf->vc=calloc(vf->links,sizeof(vorbis_info)); + + /* Try to fetch the headers, maintaining all the storage */ + if(_fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno)==-1)return(-1); + _make_decode_ready(vf); + + return 0; +} + +/* clear out the current logical bitstream decoder */ +static void _decode_clear(OggVorbis_File *vf){ + ogg_stream_clear(&vf->os); + vorbis_dsp_clear(&vf->vd); + vorbis_block_clear(&vf->vb); + vf->decode_ready=0; + + vf->bittrack=0.; + vf->samptrack=0.; +} + +/* fetch and process a packet. Handles the case where we're at a + bitstream boundary and dumps the decoding machine. If the decoding + machine is unloaded, it loads it. It also keeps pcm_offset up to + date (seek and read both use this. seek uses a special hack with + readp). + + return: -1) hole in the data (lost packet) + 0) need more date (only if readp==0)/eof + 1) got a packet +*/ + +static int _process_packet(OggVorbis_File *vf,int readp){ + ogg_page og; + + /* handle one packet. Try to fetch it from current stream state */ + /* extract packets from page */ + while(1){ + + /* process a packet if we can. If the machine isn't loaded, + neither is a page */ + if(vf->decode_ready){ + ogg_packet op; + int result=ogg_stream_packetout(&vf->os,&op); + int64_t frameno; + + /* if(result==-1)return(-1); hole in the data. For now, swallow + and go. We'll need to add a real + error code in a bit. */ + if(result>0){ + /* got a packet. process it */ + frameno=op.frameno; + if(!vorbis_synthesis(&vf->vb,&op)){ /* lazy check for lazy + header handling. The + header packets aren't + audio, so if/when we + submit them, + vorbis_synthesis will + reject them */ + + /* suck in the synthesis data and track bitrate */ + { + int oldsamples=vorbis_synthesis_pcmout(&vf->vd,NULL); + vorbis_synthesis_blockin(&vf->vd,&vf->vb); + vf->samptrack+=vorbis_synthesis_pcmout(&vf->vd,NULL)-oldsamples; + vf->bittrack+=op.bytes*8; + } + + /* update the pcm offset. */ + if(frameno!=-1 && !op.e_o_s){ + int link=(vf->seekable?vf->current_link:0); + int i,samples; + + /* this packet has a pcm_offset on it (the last packet + completed on a page carries the offset) After processing + (above), we know the pcm position of the *last* sample + ready to be returned. Find the offset of the *first* + + As an aside, this trick is inaccurate if we begin + reading anew right at the last page; the end-of-stream + frameno declares the last frame in the stream, and the + last packet of the last page may be a partial frame. + So, we need a previous frameno from an in-sequence page + to have a reference point. Thus the !op.e_o_s clause + above */ + + samples=vorbis_synthesis_pcmout(&vf->vd,NULL); + + frameno-=samples; + for(i=0;i<link;i++) + frameno+=vf->pcmlengths[i]; + vf->pcm_offset=frameno; + } + return(1); + } + } + } + + if(!readp)return(0); + if(_get_next_page(vf,&og,-1)<0)return(0); /* eof. leave unitialized */ + + /* bitrate tracking; add the header's bytes here, the body bytes + are done by packet above */ + vf->bittrack+=og.header_len*8; + + /* has our decoding just traversed a bitstream boundary? */ + if(vf->decode_ready){ + if(vf->current_serialno!=ogg_page_serialno(&og)){ + _decode_clear(vf); + } + } + + /* Do we need to load a new machine before submitting the page? */ + /* This is different in the seekable and non-seekable cases. + + In the seekable case, we already have all the header + information loaded and cached; we just initialize the machine + with it and continue on our merry way. + + In the non-seekable (streaming) case, we'll only be at a + boundary if we just left the previous logical bitstream and + we're now nominally at the header of the next bitstream + */ + + if(!vf->decode_ready){ + int link; + if(vf->seekable){ + vf->current_serialno=ogg_page_serialno(&og); + + /* match the serialno to bitstream section. We use this rather than + offset positions to avoid problems near logical bitstream + boundaries */ + for(link=0;link<vf->links;link++) + if(vf->serialnos[link]==vf->current_serialno)break; + if(link==vf->links)return(-1); /* sign of a bogus stream. error out, + leave machine uninitialized */ + + vf->current_link=link; + + ogg_stream_init(&vf->os,vf->current_serialno); + ogg_stream_reset(&vf->os); + + }else{ + /* we're streaming */ + /* fetch the three header packets, build the info struct */ + + _fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno); + vf->current_link++; + link=0; + } + + _make_decode_ready(vf); + } + ogg_stream_pagein(&vf->os,&og); + } +} + +/********************************************************************** + * The helpers are over; it's all toplevel interface from here on out */ + +/* clear out the OggVorbis_File struct */ +int ov_clear(OggVorbis_File *vf){ + if(vf){ + vorbis_block_clear(&vf->vb); + vorbis_dsp_clear(&vf->vd); + ogg_stream_clear(&vf->os); + + if(vf->vi && vf->links){ + int i; + for(i=0;i<vf->links;i++){ + vorbis_info_clear(vf->vi+i); + vorbis_comment_clear(vf->vc+i); + } + free(vf->vi); + free(vf->vc); + } + if(vf->dataoffsets)free(vf->dataoffsets); + if(vf->pcmlengths)free(vf->pcmlengths); + if(vf->serialnos)free(vf->serialnos); + if(vf->offsets)free(vf->offsets); + ogg_sync_clear(&vf->oy); + if(vf->datasource)(vf->callbacks.close_func)(vf->datasource); + memset(vf,0,sizeof(OggVorbis_File)); + } +#ifdef DEBUG_LEAKS + _VDBG_dump(); +#endif + return(0); +} + +static int _fseek64_wrap(FILE *f,int64_t off,int whence){ + return fseek(f,(int)off,whence); +} + +/* inspects the OggVorbis file and finds/documents all the logical + bitstreams contained in it. Tries to be tolerant of logical + bitstream sections that are truncated/woogie. + + return: -1) error + 0) OK +*/ + +int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){ + ov_callbacks callbacks = { + (size_t (*)(void *, size_t, size_t, void *)) fread, + (int (*)(void *, int64_t, int)) _fseek64_wrap, + (int (*)(void *)) fclose, + (long (*)(void *)) ftell + }; + + return ov_open_callbacks((void *)f, vf, initial, ibytes, callbacks); +} + + +int ov_open_callbacks(void *f,OggVorbis_File *vf,char *initial,long ibytes, + ov_callbacks callbacks) +{ + long offset=callbacks.seek_func(f,0,SEEK_CUR); + int ret; + + memset(vf,0,sizeof(OggVorbis_File)); + vf->datasource=f; + vf->callbacks = callbacks; + + /* init the framing state */ + ogg_sync_init(&vf->oy); + + /* perhaps some data was previously read into a buffer for testing + against other stream types. Allow initialization from this + previously read data (as we may be reading from a non-seekable + stream) */ + if(initial){ + char *buffer=ogg_sync_buffer(&vf->oy,ibytes); + memcpy(buffer,initial,ibytes); + ogg_sync_wrote(&vf->oy,ibytes); + } + + /* can we seek? Stevens suggests the seek test was portable */ + if(offset!=-1){ + ret=_open_seekable(vf); + }else{ + ret=_open_nonseekable(vf); + } + if(ret){ + vf->datasource=NULL; + ov_clear(vf); + } + return(ret); +} + +/* How many logical bitstreams in this physical bitstream? */ +long ov_streams(OggVorbis_File *vf){ + return vf->links; +} + +/* Is the FILE * associated with vf seekable? */ +long ov_seekable(OggVorbis_File *vf){ + return vf->seekable; +} + +/* returns the bitrate for a given logical bitstream or the entire + physical bitstream. If the file is open for random access, it will + find the *actual* average bitrate. If the file is streaming, it + returns the nominal bitrate (if set) else the average of the + upper/lower bounds (if set) else -1 (unset). + + If you want the actual bitrate field settings, get them from the + vorbis_info structs */ + +long ov_bitrate(OggVorbis_File *vf,int i){ + if(i>=vf->links)return(-1); + if(!vf->seekable && i!=0)return(ov_bitrate(vf,0)); + if(i<0){ + int64_t bits=0; + int i; + for(i=0;i<vf->links;i++) + bits+=(vf->offsets[i+1]-vf->dataoffsets[i])*8; + return(rint(bits/ov_time_total(vf,-1))); + }else{ + if(vf->seekable){ + /* return the actual bitrate */ + return(rint((vf->offsets[i+1]-vf->dataoffsets[i])*8/ov_time_total(vf,i))); + }else{ + /* return nominal if set */ + if(vf->vi[i].bitrate_nominal>0){ + return vf->vi[i].bitrate_nominal; + }else{ + if(vf->vi[i].bitrate_upper>0){ + if(vf->vi[i].bitrate_lower>0){ + return (vf->vi[i].bitrate_upper+vf->vi[i].bitrate_lower)/2; + }else{ + return vf->vi[i].bitrate_upper; + } + } + return(-1); + } + } + } +} + +/* returns the actual bitrate since last call. returns -1 if no + additional data to offer since last call (or at beginning of stream) */ +long ov_bitrate_instant(OggVorbis_File *vf){ + int link=(vf->seekable?vf->current_link:0); + long ret; + if(vf->samptrack==0)return(-1); + ret=vf->bittrack/vf->samptrack*vf->vi[link].rate+.5; + vf->bittrack=0.; + vf->samptrack=0.; + return(ret); +} + +/* Guess */ +long ov_serialnumber(OggVorbis_File *vf,int i){ + if(i>=vf->links)return(-1); + if(!vf->seekable && i>=0)return(ov_serialnumber(vf,-1)); + if(i<0){ + return(vf->current_serialno); + }else{ + return(vf->serialnos[i]); + } +} + +/* returns: total raw (compressed) length of content if i==-1 + raw (compressed) length of that logical bitstream for i==0 to n + -1 if the stream is not seekable (we can't know the length) +*/ +int64_t ov_raw_total(OggVorbis_File *vf,int i){ + if(!vf->seekable || i>=vf->links)return(-1); + if(i<0){ + long acc=0; + int i; + for(i=0;i<vf->links;i++) + acc+=ov_raw_total(vf,i); + return(acc); + }else{ + return(vf->offsets[i+1]-vf->offsets[i]); + } +} + +/* returns: total PCM length (samples) of content if i==-1 + PCM length (samples) of that logical bitstream for i==0 to n + -1 if the stream is not seekable (we can't know the length) +*/ +int64_t ov_pcm_total(OggVorbis_File *vf,int i){ + if(!vf->seekable || i>=vf->links)return(-1); + if(i<0){ + int64_t acc=0; + int i; + for(i=0;i<vf->links;i++) + acc+=ov_pcm_total(vf,i); + return(acc); + }else{ + return(vf->pcmlengths[i]); + } +} + +/* returns: total seconds of content if i==-1 + seconds in that logical bitstream for i==0 to n + -1 if the stream is not seekable (we can't know the length) +*/ +double ov_time_total(OggVorbis_File *vf,int i){ + if(!vf->seekable || i>=vf->links)return(-1); + if(i<0){ + double acc=0; + int i; + for(i=0;i<vf->links;i++) + acc+=ov_time_total(vf,i); + return(acc); + }else{ + return((float)(vf->pcmlengths[i])/vf->vi[i].rate); + } +} + +/* seek to an offset relative to the *compressed* data. This also + immediately sucks in and decodes pages to update the PCM cursor. It + will cross a logical bitstream boundary, but only if it can't get + any packets out of the tail of the bitstream we seek to (so no + surprises). + + returns zero on success, nonzero on failure */ + +int ov_raw_seek(OggVorbis_File *vf,long pos){ + + if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */ + if(pos<0 || pos>vf->offsets[vf->links])goto seek_error; + + /* clear out decoding machine state */ + vf->pcm_offset=-1; + _decode_clear(vf); + + /* seek */ + _seek_helper(vf,pos); + + /* we need to make sure the pcm_offset is set. We use the + _fetch_packet helper to process one packet with readp set, then + call it until it returns '0' with readp not set (the last packet + from a page has the 'frameno' field set, and that's how the + helper updates the offset */ + + switch(_process_packet(vf,1)){ + case 0: + /* oh, eof. There are no packets remaining. Set the pcm offset to + the end of file */ + vf->pcm_offset=ov_pcm_total(vf,-1); + return(0); + case -1: + /* error! missing data or invalid bitstream structure */ + goto seek_error; + default: + /* all OK */ + break; + } + + while(1){ + switch(_process_packet(vf,0)){ + case 0: + /* the offset is set. If it's a bogus bitstream with no offset + information, it's not but that's not our fault. We still run + gracefully, we're just missing the offset */ + return(0); + case -1: + /* error! missing data or invalid bitstream structure */ + goto seek_error; + default: + /* continue processing packets */ + break; + } + } + + seek_error: + /* dump the machine so we're in a known state */ + vf->pcm_offset=-1; + _decode_clear(vf); + return -1; +} + +/* seek to a sample offset relative to the decompressed pcm stream + + returns zero on success, nonzero on failure */ + +int ov_pcm_seek(OggVorbis_File *vf,int64_t pos){ + int link=-1; + int64_t total=ov_pcm_total(vf,-1); + + if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */ + if(pos<0 || pos>total)goto seek_error; + + /* which bitstream section does this pcm offset occur in? */ + for(link=vf->links-1;link>=0;link--){ + total-=vf->pcmlengths[link]; + if(pos>=total)break; + } + + /* search within the logical bitstream for the page with the highest + pcm_pos preceeding (or equal to) pos. There is a danger here; + missing pages or incorrect frame number information in the + bitstream could make our task impossible. Account for that (it + would be an error condition) */ + { + int64_t target=pos-total; + long end=vf->offsets[link+1]; + long begin=vf->offsets[link]; + long best=begin; + + ogg_page og; + while(begin<end){ + long bisect; + long ret; + + if(end-begin<CHUNKSIZE){ + bisect=begin; + }else{ + bisect=(end+begin)/2; + } + + _seek_helper(vf,bisect); + ret=_get_next_page(vf,&og,end-bisect); + + if(ret==-1){ + end=bisect; + }else{ + int64_t frameno=ogg_page_frameno(&og); + if(frameno<target){ + best=ret; /* raw offset of packet with frameno */ + begin=vf->offset; /* raw offset of next packet */ + }else{ + end=bisect; + } + } + } + + /* found our page. seek to it (call raw_seek). */ + + if(ov_raw_seek(vf,best))goto seek_error; + } + + /* verify result */ + if(vf->pcm_offset>=pos)goto seek_error; + if(pos>ov_pcm_total(vf,-1))goto seek_error; + + /* discard samples until we reach the desired position. Crossing a + logical bitstream boundary with abandon is OK. */ + while(vf->pcm_offset<pos){ + double **pcm; + long target=pos-vf->pcm_offset; + long samples=vorbis_synthesis_pcmout(&vf->vd,&pcm); + + if(samples>target)samples=target; + vorbis_synthesis_read(&vf->vd,samples); + vf->pcm_offset+=samples; + + if(samples<target) + if(_process_packet(vf,1)==0) + vf->pcm_offset=ov_pcm_total(vf,-1); /* eof */ + } + return 0; + + seek_error: + /* dump machine so we're in a known state */ + vf->pcm_offset=-1; + _decode_clear(vf); + return -1; +} + +/* seek to a playback time relative to the decompressed pcm stream + returns zero on success, nonzero on failure */ +int ov_time_seek(OggVorbis_File *vf,double seconds){ + /* translate time to PCM position and call ov_pcm_seek */ + + int link=-1; + int64_t pcm_total=ov_pcm_total(vf,-1); + double time_total=ov_time_total(vf,-1); + + if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */ + if(seconds<0 || seconds>time_total)goto seek_error; + + /* which bitstream section does this time offset occur in? */ + for(link=vf->links-1;link>=0;link--){ + pcm_total-=vf->pcmlengths[link]; + time_total-=ov_time_total(vf,link); + if(seconds>=time_total)break; + } + + /* enough information to convert time offset to pcm offset */ + { + int64_t target=pcm_total+(seconds-time_total)*vf->vi[link].rate; + return(ov_pcm_seek(vf,target)); + } + + seek_error: + /* dump machine so we're in a known state */ + vf->pcm_offset=-1; + _decode_clear(vf); + return -1; +} + +/* tell the current stream offset cursor. Note that seek followed by + tell will likely not give the set offset due to caching */ +int64_t ov_raw_tell(OggVorbis_File *vf){ + return(vf->offset); +} + +/* return PCM offset (sample) of next PCM sample to be read */ +int64_t ov_pcm_tell(OggVorbis_File *vf){ + return(vf->pcm_offset); +} + +/* return time offset (seconds) of next PCM sample to be read */ +double ov_time_tell(OggVorbis_File *vf){ + /* translate time to PCM position and call ov_pcm_seek */ + + int link=-1; + int64_t pcm_total=0; + double time_total=0.; + + if(vf->seekable){ + pcm_total=ov_pcm_total(vf,-1); + time_total=ov_time_total(vf,-1); + + /* which bitstream section does this time offset occur in? */ + for(link=vf->links-1;link>=0;link--){ + pcm_total-=vf->pcmlengths[link]; + time_total-=ov_time_total(vf,link); + if(vf->pcm_offset>=pcm_total)break; + } + } + + return((double)time_total+(double)(vf->pcm_offset-pcm_total)/vf->vi[link].rate); +} + +/* link: -1) return the vorbis_info struct for the bitstream section + currently being decoded + 0-n) to request information for a specific bitstream section + + In the case of a non-seekable bitstream, any call returns the + current bitstream. NULL in the case that the machine is not + initialized */ + +vorbis_info *ov_info(OggVorbis_File *vf,int link){ + if(vf->seekable){ + if(link<0) + if(vf->decode_ready) + return vf->vi+vf->current_link; + else + return NULL; + else + if(link>=vf->links) + return NULL; + else + return vf->vi+link; + }else{ + if(vf->decode_ready) + return vf->vi; + else + return NULL; + } +} + +/* grr, strong typing, grr, no templates/inheritence, grr */ +vorbis_comment *ov_comment(OggVorbis_File *vf,int link){ + if(vf->seekable){ + if(link<0) + if(vf->decode_ready) + return vf->vc+vf->current_link; + else + return NULL; + else + if(link>=vf->links) + return NULL; + else + return vf->vc+link; + }else{ + if(vf->decode_ready) + return vf->vc; + else + return NULL; + } +} + +int host_is_big_endian() { + short pattern = 0xbabe; + unsigned char *bytewise = (unsigned char *)&pattern; + if (bytewise[0] == 0xba) return 1; + + assert(bytewise[0] == 0xbe); + return 0; +} + +/* up to this point, everything could more or less hide the multiple + logical bitstream nature of chaining from the toplevel application + if the toplevel application didn't particularly care. However, at + the point that we actually read audio back, the multiple-section + nature must surface: Multiple bitstream sections do not necessarily + have to have the same number of channels or sampling rate. + + ov_read returns the sequential logical bitstream number currently + being decoded along with the PCM data in order that the toplevel + application can take action on channel/sample rate changes. This + number will be incremented even for streamed (non-seekable) streams + (for seekable streams, it represents the actual logical bitstream + index within the physical bitstream. Note that the accessor + functions above are aware of this dichotomy). + + input values: buffer) a buffer to hold packed PCM data for return + length) the byte length requested to be placed into buffer + bigendianp) should the data be packed LSB first (0) or + MSB first (1) + word) word size for output. currently 1 (byte) or + 2 (16 bit short) + + return values: -1) error/hole in data + 0) EOF + n) number of bytes of PCM actually returned. The + below works on a packet-by-packet basis, so the + return length is not related to the 'length' passed + in, just guaranteed to fit. + + *section) set to the logical bitstream number */ + +long ov_read(OggVorbis_File *vf,char *buffer,int length, + int bigendianp,int word,int sgned,int *bitstream){ + int i,j; + int host_endian = host_is_big_endian(); + + while(1){ + if(vf->decode_ready){ + double **pcm; + long samples=vorbis_synthesis_pcmout(&vf->vd,&pcm); + if(samples){ + /* yay! proceed to pack data into the byte buffer */ + + long channels=ov_info(vf,-1)->channels; + long bytespersample=word * channels; + if(samples>length/bytespersample)samples=length/bytespersample; + + /* a tight loop to pack each size */ + { + int val; + if(word==1){ + int off=(sgned?0:128); + for(j=0;j<samples;j++) + for(i=0;i<channels;i++){ + val=(int)(pcm[i][j]*128. + 0.5); + if(val>127)val=127; + else if(val<-128)val=-128; + *buffer++=val+off; + } + }else{ + int off=(sgned?0:32768); + + if(host_endian==bigendianp){ + if(sgned){ + for(i=0;i<channels;i++) { /* It's faster in this order */ + double *src=pcm[i]; + short *dest=((short *)buffer)+i; + for(j=0;j<samples;j++) { + val=(int)(src[j]*32768. + 0.5); + if(val>32767)val=32767; + else if(val<-32768)val=-32768; + *dest=val; + dest+=channels; + } + } + }else{ + for(i=0;i<channels;i++) { + double *src=pcm[i]; + short *dest=((short *)buffer)+i; + for(j=0;j<samples;j++) { + val=(int)(src[j]*32768. + 0.5); + if(val>32767)val=32767; + else if(val<-32768)val=-32768; + *dest=val+off; + dest+=channels; + } + } + } + }else if(bigendianp){ + for(j=0;j<samples;j++) + for(i=0;i<channels;i++){ + val=(int)(pcm[i][j]*32768. + 0.5); + if(val>32767)val=32767; + else if(val<-32768)val=-32768; + val+=off; + *buffer++=(val>>8); + *buffer++=(val&0xff); + } + }else{ + int val; + for(j=0;j<samples;j++) + for(i=0;i<channels;i++){ + val=(int)(pcm[i][j]*32768. + 0.5); + if(val>32767)val=32767; + else if(val<-32768)val=-32768; + val+=off; + *buffer++=(val&0xff); + *buffer++=(val>>8); + } + + } + } + } + + vorbis_synthesis_read(&vf->vd,samples); + vf->pcm_offset+=samples; + if(bitstream)*bitstream=vf->current_link; + return(samples*bytespersample); + } + } + + /* suck in another packet */ + switch(_process_packet(vf,1)){ + case 0: + return(0); + case -1: + return -1; + default: + break; + } + } +} + + + + |