/******************************************************************** * * * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * * * * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2015 * * by the Xiph.Org Foundation https://xiph.org/ * * * ******************************************************************** function: stdio-based convenience library for opening/seeking/decoding ********************************************************************/ #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> #include <math.h> #include "vorbis/codec.h" /* we don't need or want the static callback symbols here */ #define OV_EXCLUDE_STATIC_CALLBACKS #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 coarse 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 … #define READSIZE … static long _get_data(OggVorbis_File *vf){ … } /* save a tiny smidge of verbosity to make the code more readable */ static int _seek_helper(OggVorbis_File *vf,ogg_int64_t offset){ … } /* 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: <0) did not find a page (OV_FALSE, OV_EOF, OV_EREAD) n) found a page at absolute offset n */ static ogg_int64_t _get_next_page(OggVorbis_File *vf,ogg_page *og, ogg_int64_t boundary){ … } /* find the latest page beginning before the passed in position. Much dirtier than the above as Ogg doesn't have any backward search linkage. no 'readp' as it will certainly have to read. */ /* returns offset or OV_EREAD, OV_FAULT */ static ogg_int64_t _get_prev_page(OggVorbis_File *vf,ogg_int64_t begin,ogg_page *og){ … } static void _add_serialno(ogg_page *og,long **serialno_list, int *n){ … } /* returns nonzero if found */ static int _lookup_serialno(long s, long *serialno_list, int n){ … } static int _lookup_page_serialno(ogg_page *og, long *serialno_list, int n){ … } /* performs the same search as _get_prev_page, but prefers pages of the specified serial number. If a page of the specified serialno is spotted during the seek-back-and-read-forward, it will return the info of last page of the matching serial number instead of the very last page. If no page of the specified serialno is seen, it will return the info of last page and alter *serialno. */ static ogg_int64_t _get_prev_page_serial(OggVorbis_File *vf, ogg_int64_t begin, long *serial_list, int serial_n, int *serialno, ogg_int64_t *granpos){ … } /* 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_list, int *serialno_n, ogg_page *og_ptr){ … } /* Starting from current cursor position, get initial PCM offset of next page. Consumes the page in the process without decoding audio, however this is only called during stream parsing upon seekable open. */ static ogg_int64_t _initial_pcmoffset(OggVorbis_File *vf, vorbis_info *vi){ … } /* 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 int _bisect_forward_serialno(OggVorbis_File *vf, ogg_int64_t begin, ogg_int64_t searched, ogg_int64_t end, ogg_int64_t endgran, int endserial, long *currentno_list, int currentnos, long m){ … } static int _make_decode_ready(OggVorbis_File *vf){ … } static int _open_seekable2(OggVorbis_File *vf){ … } /* clear out the current logical bitstream decoder */ static void _decode_clear(OggVorbis_File *vf){ … } /* 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: <0) error, OV_HOLE (lost packet) or OV_EOF 0) need more data (only if readp==0) 1) got a packet */ static int _fetch_and_process_packet(OggVorbis_File *vf, ogg_packet *op_in, int readp, int spanp){ … } /* if, eg, 64 bit stdio is configured by default, this will build with fseek64 */ static int _fseek64_wrap(FILE *f,ogg_int64_t off,int whence){ … } static int _ov_open1(void *f,OggVorbis_File *vf,const char *initial, long ibytes, ov_callbacks callbacks){ … } static int _ov_open2(OggVorbis_File *vf){ … } /* clear out the OggVorbis_File struct */ int ov_clear(OggVorbis_File *vf){ … } /* 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_callbacks(void *f,OggVorbis_File *vf, const char *initial,long ibytes,ov_callbacks callbacks){ … } int ov_open(FILE *f,OggVorbis_File *vf,const char *initial,long ibytes){ … } int ov_fopen(const char *path,OggVorbis_File *vf){ … } /* cheap hack for game usage where downsampling is desirable; there's no need for SRC as we can just do it cheaply in libvorbis. */ int ov_halfrate(OggVorbis_File *vf,int flag){ … } int ov_halfrate_p(OggVorbis_File *vf){ … } /* Only partially open the vorbis file; test for Vorbisness, and load the headers for the first chain. Do not seek (although test for seekability). Use ov_test_open to finish opening the file, else ov_clear to close/free it. Same return codes as open. Note that vorbisfile does _not_ take ownership of the file if the call fails; the calling applicaiton is responsible for closing the file if this call returns an error. */ int ov_test_callbacks(void *f,OggVorbis_File *vf, const char *initial,long ibytes,ov_callbacks callbacks) { … } int ov_test(FILE *f,OggVorbis_File *vf,const char *initial,long ibytes){ … } int ov_test_open(OggVorbis_File *vf){ … } /* How many logical bitstreams in this physical bitstream? */ long ov_streams(OggVorbis_File *vf){ … } /* Is the FILE * associated with vf seekable? */ long ov_seekable(OggVorbis_File *vf){ … } /* 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){ … } /* returns the actual bitrate since last call. returns -1 if no additional data to offer since last call (or at beginning of stream), EINVAL if stream is only partially open */ long ov_bitrate_instant(OggVorbis_File *vf){ … } /* Guess */ long ov_serialnumber(OggVorbis_File *vf,int i){ … } /* returns: total raw (compressed) length of content if i==-1 raw (compressed) length of that logical bitstream for i==0 to n OV_EINVAL if the stream is not seekable (we can't know the length) or if stream is only partially open */ ogg_int64_t ov_raw_total(OggVorbis_File *vf,int i){ … } /* returns: total PCM length (samples) of content if i==-1 PCM length (samples) of that logical bitstream for i==0 to n OV_EINVAL if the stream is not seekable (we can't know the length) or only partially open */ ogg_int64_t ov_pcm_total(OggVorbis_File *vf,int i){ … } /* returns: total seconds of content if i==-1 seconds in that logical bitstream for i==0 to n OV_EINVAL if the stream is not seekable (we can't know the length) or only partially open */ double ov_time_total(OggVorbis_File *vf,int i){ … } /* seek to an offset relative to the *compressed* data. This also scans packets 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,ogg_int64_t pos){ … } /* Page granularity seek (faster than sample granularity because we don't do the last bit of decode to find a specific sample). Seek to the last [granule marked] page preceding the specified pos location, such that decoding past the returned point will quickly arrive at the requested position. */ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){ … } /* 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,ogg_int64_t pos){ … } /* 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){ … } /* page-granularity version of ov_time_seek returns zero on success, nonzero on failure */ int ov_time_seek_page(OggVorbis_File *vf,double seconds){ … } /* tell the current stream offset cursor. Note that seek followed by tell will likely not give the set offset due to caching */ ogg_int64_t ov_raw_tell(OggVorbis_File *vf){ … } /* return PCM offset (sample) of next PCM sample to be read */ ogg_int64_t ov_pcm_tell(OggVorbis_File *vf){ … } /* return time offset (seconds) of next PCM sample to be read */ double ov_time_tell(OggVorbis_File *vf){ … } /* 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){ … } /* grr, strong typing, grr, no templates/inheritence, grr */ vorbis_comment *ov_comment(OggVorbis_File *vf,int link){ … } static int host_is_big_endian() { … } /* 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). ov_read_filter is exactly the same as ov_read except that it processes the decoded audio data through a filter before packing it into the requested format. This gives greater accuracy than applying a filter after the audio has been converted into integral PCM. 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: <0) error/hole in data (OV_HOLE), partial open (OV_EINVAL) 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_filter(OggVorbis_File *vf,char *buffer,int length, int bigendianp,int word,int sgned,int *bitstream, void (*filter)(float **pcm,long channels,long samples,void *filter_param),void *filter_param){ … } long ov_read(OggVorbis_File *vf,char *buffer,int length, int bigendianp,int word,int sgned,int *bitstream){ … } /* input values: pcm_channels) a float vector per channel of output length) the sample length being read by the app return values: <0) error/hole in data (OV_HOLE), partial open (OV_EINVAL) 0) EOF n) number of samples 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_float(OggVorbis_File *vf,float ***pcm_channels,int length, int *bitstream){ … } extern const float *vorbis_window(vorbis_dsp_state *v,int W); static void _ov_splice(float **pcm,float **lappcm, int n1, int n2, int ch1, int ch2, const float *w1, const float *w2){ … } /* make sure vf is INITSET */ static int _ov_initset(OggVorbis_File *vf){ … } /* make sure vf is INITSET and that we have a primed buffer; if we're crosslapping at a stream section boundary, this also makes sure we're sanity checking against the right stream information */ static int _ov_initprime(OggVorbis_File *vf){ … } /* grab enough data for lapping from vf; this may be in the form of unreturned, already-decoded pcm, remaining PCM we will need to decode, or synthetic postextrapolation from last packets. */ static void _ov_getlap(OggVorbis_File *vf,vorbis_info *vi,vorbis_dsp_state *vd, float **lappcm,int lapsize){ … } /* this sets up crosslapping of a sample by using trailing data from sample 1 and lapping it into the windowing buffer of sample 2 */ int ov_crosslap(OggVorbis_File *vf1, OggVorbis_File *vf2){ … } static int _ov_64_seek_lap(OggVorbis_File *vf,ogg_int64_t pos, int (*localseek)(OggVorbis_File *,ogg_int64_t)){ … } int ov_raw_seek_lap(OggVorbis_File *vf,ogg_int64_t pos){ … } int ov_pcm_seek_lap(OggVorbis_File *vf,ogg_int64_t pos){ … } int ov_pcm_seek_page_lap(OggVorbis_File *vf,ogg_int64_t pos){ … } static int _ov_d_seek_lap(OggVorbis_File *vf,double pos, int (*localseek)(OggVorbis_File *,double)){ … } int ov_time_seek_lap(OggVorbis_File *vf,double pos){ … } int ov_time_seek_page_lap(OggVorbis_File *vf,double pos){ … }
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