Wed Aug 15 01:25:35 2007

Asterisk developer's documentation


translate.h File Reference

Support for translation of data formats. More...

#include "asterisk/frame.h"
#include "asterisk/plc.h"
#include "asterisk/linkedlists.h"

Include dependency graph for translate.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures

struct  ast_trans_pvt
 Default structure for translators, with the basic fields and buffers, all allocated as part of the same chunk of memory. The buffer is preceded by AST_FRIENDLY_OFFSET bytes in front of the user portion. 'buf' points right after this space. More...
struct  ast_translator
 Descriptor of a translator. Name, callbacks, and various options related to run-time operation (size of buffers, auxiliary descriptors, etc). More...

Defines

#define ast_register_translator(t)   __ast_register_translator(t, ast_module_info->self)
#define MAX_FORMAT   32

Functions

int __ast_register_translator (struct ast_translator *t, struct ast_module *module)
 Register a translator This registers a codec translator with asterisk.
struct ast_frameast_trans_frameout (struct ast_trans_pvt *pvt, int datalen, int samples)
 generic frameout function
struct ast_frameast_translate (struct ast_trans_pvt *tr, struct ast_frame *f, int consume)
 translates one or more frames Apply an input frame into the translator and receive zero or one output frames. Consume determines whether the original frame should be freed
unsigned int ast_translate_available_formats (unsigned int dest, unsigned int src)
 Mask off unavailable formats from a format bitmask.
unsigned int ast_translate_path_steps (unsigned int dest, unsigned int src)
 Returns the number of steps required to convert from 'src' to 'dest'.
void ast_translator_activate (struct ast_translator *t)
 Activate a previously deactivated translator.
int ast_translator_best_choice (int *dsts, int *srcs)
 Chooses the best translation path.
struct ast_trans_pvtast_translator_build_path (int dest, int source)
 Builds a translator path Build a path (possibly NULL) from source to dest.
void ast_translator_deactivate (struct ast_translator *t)
 Deactivate a translator.
void ast_translator_free_path (struct ast_trans_pvt *tr)
 Frees a translator path Frees the given translator path structure.
int ast_unregister_translator (struct ast_translator *t)
 Unregister a translator Unregisters the given tranlator.


Detailed Description

Support for translation of data formats.

Definition in file translate.h.


Define Documentation

#define ast_register_translator ( t   )     __ast_register_translator(t, ast_module_info->self)

Definition at line 161 of file translate.h.

Referenced by load_module(), and register_translator().

#define MAX_FORMAT   32

Definition at line 27 of file translate.h.

Referenced by __ast_register_translator(), ast_translator_best_choice(), and rebuild_matrix().


Function Documentation

int __ast_register_translator ( struct ast_translator t,
struct ast_module mod 
)

Register a translator This registers a codec translator with asterisk.

Parameters:
t populated ast_translator structure
module handle to the module that owns this translator
Returns:
0 on success, -1 on failure

Definition at line 649 of file translate.c.

References ast_translator::active, ast_cli_register_multiple(), AST_FORMAT_SLINEAR, ast_getformatname(), AST_LIST_INSERT_BEFORE_CURRENT, AST_LIST_INSERT_HEAD, AST_LIST_LOCK, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, AST_LIST_UNLOCK, ast_log(), ast_verbose(), ast_translator::buf_size, ast_translator::buffer_samples, calc_cost(), COLOR_BLACK, COLOR_MAGENTA, ast_translator::cost, default_frameout(), ast_translator::dstfmt, ast_translator::frameout, LOG_WARNING, MAX_FORMAT, ast_translator::module, ast_translator::name, option_verbose, ast_translator::plc_samples, powerof(), rebuild_matrix(), ast_translator::srcfmt, term_color(), and VERBOSE_PREFIX_2.

00650 {
00651    static int added_cli = 0;
00652    struct ast_translator *u;
00653 
00654    if (!mod) {
00655       ast_log(LOG_WARNING, "Missing module pointer, you need to supply one\n");
00656       return -1;
00657    }
00658 
00659    if (!t->buf_size) {
00660       ast_log(LOG_WARNING, "empty buf size, you need to supply one\n");
00661       return -1;
00662    }
00663 
00664    t->module = mod;
00665 
00666    t->srcfmt = powerof(t->srcfmt);
00667    t->dstfmt = powerof(t->dstfmt);
00668    t->active = 1;
00669 
00670    if (t->plc_samples) {
00671       if (t->buffer_samples < t->plc_samples) {
00672          ast_log(LOG_WARNING, "plc_samples %d buffer_samples %d\n",
00673             t->plc_samples, t->buffer_samples);
00674          return -1;
00675       }
00676       if (t->dstfmt != powerof(AST_FORMAT_SLINEAR))
00677          ast_log(LOG_WARNING, "plc_samples %d format %x\n",
00678             t->plc_samples, t->dstfmt);
00679    }
00680    if (t->srcfmt >= MAX_FORMAT) {
00681       ast_log(LOG_WARNING, "Source format %s is larger than MAX_FORMAT\n", ast_getformatname(t->srcfmt));
00682       return -1;
00683    }
00684 
00685    if (t->dstfmt >= MAX_FORMAT) {
00686       ast_log(LOG_WARNING, "Destination format %s is larger than MAX_FORMAT\n", ast_getformatname(t->dstfmt));
00687       return -1;
00688    }
00689 
00690    if (t->buf_size) {
00691                /*
00692       * Align buf_size properly, rounding up to the machine-specific
00693       * alignment for pointers.
00694       */
00695       struct _test_align { void *a, *b; } p;
00696       int align = (char *)&p.b - (char *)&p.a;
00697 
00698       t->buf_size = ((t->buf_size + align - 1) / align) * align;
00699    }
00700 
00701    if (t->frameout == NULL)
00702       t->frameout = default_frameout;
00703   
00704    calc_cost(t, 1);
00705 
00706    if (option_verbose > 1) {
00707       char tmp[80];
00708 
00709       ast_verbose(VERBOSE_PREFIX_2 "Registered translator '%s' from format %s to %s, cost %d\n",
00710              term_color(tmp, t->name, COLOR_MAGENTA, COLOR_BLACK, sizeof(tmp)),
00711              ast_getformatname(1 << t->srcfmt), ast_getformatname(1 << t->dstfmt), t->cost);
00712    }
00713 
00714    if (!added_cli) {
00715       ast_cli_register_multiple(cli_translate, sizeof(cli_translate) / sizeof(struct ast_cli_entry));
00716       added_cli++;
00717    }
00718 
00719    AST_LIST_LOCK(&translators);
00720 
00721    /* find any existing translators that provide this same srcfmt/dstfmt,
00722       and put this one in order based on cost */
00723    AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, u, list) {
00724       if ((u->srcfmt == t->srcfmt) &&
00725           (u->dstfmt == t->dstfmt) &&
00726           (u->cost > t->cost)) {
00727          AST_LIST_INSERT_BEFORE_CURRENT(&translators, t, list);
00728          t = NULL;
00729       }
00730    }
00731    AST_LIST_TRAVERSE_SAFE_END;
00732 
00733    /* if no existing translator was found for this format combination,
00734       add it to the beginning of the list */
00735    if (t)
00736       AST_LIST_INSERT_HEAD(&translators, t, list);
00737 
00738    rebuild_matrix(0);
00739 
00740    AST_LIST_UNLOCK(&translators);
00741 
00742    return 0;
00743 }

struct ast_frame* ast_trans_frameout ( struct ast_trans_pvt pvt,
int  datalen,
int  samples 
) [read]

generic frameout function

Definition at line 209 of file translate.c.

References AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_frame::data, ast_trans_pvt::datalen, ast_frame::datalen, ast_translator::dstfmt, ast_trans_pvt::f, f, ast_frame::frametype, ast_frame::mallocd, ast_translator::name, ast_frame::offset, ast_trans_pvt::outbuf, ast_trans_pvt::samples, ast_frame::samples, ast_frame::src, ast_frame::subclass, and ast_trans_pvt::t.

00211 {
00212    struct ast_frame *f = &pvt->f;
00213 
00214         if (samples)
00215       f->samples = samples;
00216    else {
00217       if (pvt->samples == 0)
00218          return NULL;
00219       f->samples = pvt->samples;
00220       pvt->samples = 0;
00221    }
00222    if (datalen)
00223       f->datalen = datalen;
00224    else {
00225       f->datalen = pvt->datalen;
00226       pvt->datalen = 0;
00227    }
00228 
00229    f->frametype = AST_FRAME_VOICE;
00230    f->subclass = 1 << (pvt->t->dstfmt);
00231    f->mallocd = 0;
00232    f->offset = AST_FRIENDLY_OFFSET;
00233    f->src = pvt->t->name;
00234    f->data = pvt->outbuf;
00235    return f;
00236 }

struct ast_frame* ast_translate ( struct ast_trans_pvt path,
struct ast_frame f,
int  consume 
) [read]

translates one or more frames Apply an input frame into the translator and receive zero or one output frames. Consume determines whether the original frame should be freed

Parameters:
tr translator structure to use for translation
f frame to translate
consume Whether or not to free the original frame
Returns:
an ast_frame of the new translation format on success, NULL on failure

Definition at line 295 of file translate.c.

References AST_FRAME_CNG, ast_frfree(), ast_tvadd(), ast_tvsub(), ast_frame::delivery, framein(), ast_frame::frametype, ast_frame::has_timing_info, ast_frame::len, len, ast_trans_pvt::next, ast_trans_pvt::nextin, ast_trans_pvt::nextout, ast_frame::samples, ast_frame::seqno, and ast_frame::ts.

00296 {
00297    struct ast_trans_pvt *p = path;
00298    struct ast_frame *out = f;
00299    struct timeval delivery;
00300    int has_timing_info;
00301    long ts;
00302    long len;
00303    int seqno;
00304 
00305    has_timing_info = f->has_timing_info;
00306    ts = f->ts;
00307    len = f->len;
00308    seqno = f->seqno;
00309 
00310    /* XXX hmmm... check this below */
00311    if (!ast_tvzero(f->delivery)) {
00312       if (!ast_tvzero(path->nextin)) {
00313          /* Make sure this is in line with what we were expecting */
00314          if (!ast_tveq(path->nextin, f->delivery)) {
00315             /* The time has changed between what we expected and this
00316                most recent time on the new packet.  If we have a
00317                valid prediction adjust our output time appropriately */
00318             if (!ast_tvzero(path->nextout)) {
00319                path->nextout = ast_tvadd(path->nextout,
00320                           ast_tvsub(f->delivery, path->nextin));
00321             }
00322             path->nextin = f->delivery;
00323          }
00324       } else {
00325          /* This is our first pass.  Make sure the timing looks good */
00326          path->nextin = f->delivery;
00327          path->nextout = f->delivery;
00328       }
00329       /* Predict next incoming sample */
00330       path->nextin = ast_tvadd(path->nextin, ast_samp2tv(f->samples, 8000));
00331    }
00332    delivery = f->delivery;
00333    for ( ; out && p ; p = p->next) {
00334       framein(p, out);
00335       out = p->t->frameout(p);
00336    }
00337    if (consume)
00338       ast_frfree(f);
00339    if (out == NULL)
00340       return NULL;
00341    /* we have a frame, play with times */
00342    if (!ast_tvzero(delivery)) {
00343       /* Regenerate prediction after a discontinuity */
00344       if (ast_tvzero(path->nextout))
00345          path->nextout = ast_tvnow();
00346 
00347       /* Use next predicted outgoing timestamp */
00348       out->delivery = path->nextout;
00349       
00350       /* Predict next outgoing timestamp from samples in this
00351          frame. */
00352       path->nextout = ast_tvadd(path->nextout, ast_samp2tv( out->samples, 8000));
00353    } else {
00354       out->delivery = ast_tv(0, 0);
00355       out->has_timing_info = has_timing_info;
00356       if (has_timing_info) {
00357          out->ts = ts;
00358          out->len = len;
00359          out->seqno = seqno;
00360       }
00361    }
00362    /* Invalidate prediction if we're entering a silence period */
00363    if (out->frametype == AST_FRAME_CNG)
00364       path->nextout = ast_tv(0, 0);
00365    return out;
00366 }

unsigned int ast_translate_available_formats ( unsigned int  dest,
unsigned int  src 
)

Mask off unavailable formats from a format bitmask.

Parameters:
dest possible destination formats
src source formats
Returns:
the destination formats that are available in the source or translatable
The result will include all formats from 'dest' that are either present in 'src' or translatable from a format present in 'src'.

Note that only a single audio format and a single video format can be present in 'src', or the function will produce unexpected results.

Definition at line 854 of file translate.c.

References AST_FORMAT_AUDIO_MASK, AST_FORMAT_MAX_AUDIO, AST_FORMAT_MAX_VIDEO, AST_FORMAT_VIDEO_MASK, AST_LIST_LOCK, AST_LIST_UNLOCK, powerof(), and tr_matrix.

00855 {
00856    unsigned int res = dest;
00857    unsigned int x;
00858    unsigned int src_audio = src & AST_FORMAT_AUDIO_MASK;
00859    unsigned int src_video = src & AST_FORMAT_VIDEO_MASK;
00860 
00861    /* if we don't have a source format, we just have to try all
00862       possible destination formats */
00863    if (!src)
00864       return dest;
00865 
00866    /* If we have a source audio format, get its format index */
00867    if (src_audio)
00868       src_audio = powerof(src_audio);
00869 
00870    /* If we have a source video format, get its format index */
00871    if (src_video)
00872       src_video = powerof(src_video);
00873 
00874    AST_LIST_LOCK(&translators);
00875 
00876    /* For a given source audio format, traverse the list of
00877       known audio formats to determine whether there exists
00878       a translation path from the source format to the
00879       destination format. */
00880    for (x = 1; src_audio && x < AST_FORMAT_MAX_AUDIO; x <<= 1) {
00881       /* if this is not a desired format, nothing to do */
00882       if (!dest & x)
00883          continue;
00884 
00885       /* if the source is supplying this format, then
00886          we can leave it in the result */
00887       if (src & x)
00888          continue;
00889 
00890       /* if we don't have a translation path from the src
00891          to this format, remove it from the result */
00892       if (!tr_matrix[src_audio][powerof(x)].step) {
00893          res &= ~x;
00894          continue;
00895       }
00896 
00897       /* now check the opposite direction */
00898       if (!tr_matrix[powerof(x)][src_audio].step)
00899          res &= ~x;
00900    }
00901 
00902    /* For a given source video format, traverse the list of
00903       known video formats to determine whether there exists
00904       a translation path from the source format to the
00905       destination format. */
00906    for (; src_video && x < AST_FORMAT_MAX_VIDEO; x <<= 1) {
00907       /* if this is not a desired format, nothing to do */
00908       if (!dest & x)
00909          continue;
00910 
00911       /* if the source is supplying this format, then
00912          we can leave it in the result */
00913       if (src & x)
00914          continue;
00915 
00916       /* if we don't have a translation path from the src
00917          to this format, remove it from the result */
00918       if (!tr_matrix[src_video][powerof(x)].step) {
00919          res &= ~x;
00920          continue;
00921       }
00922 
00923       /* now check the opposite direction */
00924       if (!tr_matrix[powerof(x)][src_video].step)
00925          res &= ~x;
00926    }
00927 
00928    AST_LIST_UNLOCK(&translators);
00929 
00930    return res;
00931 }

unsigned int ast_translate_path_steps ( unsigned int  dest,
unsigned int  src 
)

Returns the number of steps required to convert from 'src' to 'dest'.

Parameters:
dest destination format
src source format
Returns:
the number of translation steps required, or -1 if no path is available

Definition at line 836 of file translate.c.

References AST_LIST_LOCK, AST_LIST_UNLOCK, translator_path::multistep, powerof(), and tr_matrix.

00837 {
00838    unsigned int res = -1;
00839 
00840    /* convert bitwise format numbers into array indices */
00841    src = powerof(src);
00842    dest = powerof(dest);
00843 
00844    AST_LIST_LOCK(&translators);
00845 
00846    if (tr_matrix[src][dest].step)
00847       res = tr_matrix[src][dest].multistep + 1;
00848 
00849    AST_LIST_UNLOCK(&translators);
00850 
00851    return res;
00852 }

void ast_translator_activate ( struct ast_translator t  ) 

Activate a previously deactivated translator.

Parameters:
t translator to activate
Returns:
nothing
Enables the specified translator for use.

Definition at line 772 of file translate.c.

References ast_translator::active, AST_LIST_LOCK, AST_LIST_UNLOCK, and rebuild_matrix().

00773 {
00774    AST_LIST_LOCK(&translators);
00775    t->active = 1;
00776    rebuild_matrix(0);
00777    AST_LIST_UNLOCK(&translators);
00778 }

int ast_translator_best_choice ( int *  dst,
int *  srcs 
)

Chooses the best translation path.

Given a list of sources, and a designed destination format, which should I choose?

Returns:
Returns 0 on success, -1 if no path could be found.
Note:
Modifies dests and srcs in place

Definition at line 789 of file translate.c.

References AST_LIST_LOCK, AST_LIST_UNLOCK, translator_path::cost, ast_translator::cost, MAX_FORMAT, translator_path::multistep, and tr_matrix.

00790 {
00791    int x,y;
00792    int best = -1;
00793    int bestdst = 0;
00794    int cur, cursrc;
00795    int besttime = INT_MAX;
00796    int beststeps = INT_MAX;
00797    int common = (*dst) & (*srcs);   /* are there common formats ? */
00798 
00799    if (common) { /* yes, pick one and return */
00800       for (cur = 1, y = 0; y < MAX_FORMAT; cur <<= 1, y++) {
00801          if (cur & common) /* guaranteed to find one */
00802             break;
00803       }
00804       /* We are done, this is a common format to both. */
00805       *srcs = *dst = cur;
00806       return 0;
00807    } else { /* No, we will need to translate */
00808       AST_LIST_LOCK(&translators);
00809       for (cur = 1, y = 0; y < MAX_FORMAT; cur <<= 1, y++) {
00810          if (! (cur & *dst))
00811             continue;
00812          for (cursrc = 1, x = 0; x < MAX_FORMAT; cursrc <<= 1, x++) {
00813             if (!(*srcs & cursrc) || !tr_matrix[x][y].step ||
00814                 tr_matrix[x][y].cost >  besttime)
00815                continue;   /* not existing or no better */
00816             if (tr_matrix[x][y].cost < besttime ||
00817                 tr_matrix[x][y].multistep < beststeps) {
00818                /* better than what we have so far */
00819                best = cursrc;
00820                bestdst = cur;
00821                besttime = tr_matrix[x][y].cost;
00822                beststeps = tr_matrix[x][y].multistep;
00823             }
00824          }
00825       }
00826       AST_LIST_UNLOCK(&translators);
00827       if (best > -1) {
00828          *srcs = best;
00829          *dst = bestdst;
00830          best = 0;
00831       }
00832       return best;
00833    }
00834 }

struct ast_trans_pvt* ast_translator_build_path ( int  dest,
int  source 
) [read]

Builds a translator path Build a path (possibly NULL) from source to dest.

Parameters:
dest destination format
source source format
Returns:
ast_trans_pvt on success, NULL on failure

Definition at line 255 of file translate.c.

References ast_getformatname(), AST_LIST_LOCK, AST_LIST_UNLOCK, ast_log(), ast_translator_free_path(), ast_translator::dstfmt, LOG_WARNING, newpvt(), ast_trans_pvt::next, ast_trans_pvt::nextin, ast_trans_pvt::nextout, powerof(), translator_path::step, ast_trans_pvt::t, t, and tr_matrix.

00256 {
00257    struct ast_trans_pvt *head = NULL, *tail = NULL;
00258    
00259    source = powerof(source);
00260    dest = powerof(dest);
00261    
00262    AST_LIST_LOCK(&translators);
00263 
00264    while (source != dest) {
00265       struct ast_trans_pvt *cur;
00266       struct ast_translator *t = tr_matrix[source][dest].step;
00267       if (!t) {
00268          ast_log(LOG_WARNING, "No translator path from %s to %s\n", 
00269             ast_getformatname(source), ast_getformatname(dest));
00270          AST_LIST_UNLOCK(&translators);
00271          return NULL;
00272       }
00273       if (!(cur = newpvt(t))) {
00274          ast_log(LOG_WARNING, "Failed to build translator step from %d to %d\n", source, dest);
00275          if (head)
00276             ast_translator_free_path(head);  
00277          AST_LIST_UNLOCK(&translators);
00278          return NULL;
00279       }
00280       if (!head)
00281          head = cur;
00282       else
00283          tail->next = cur;
00284       tail = cur;
00285       cur->nextin = cur->nextout = ast_tv(0, 0);
00286       /* Keep going if this isn't the final destination */
00287       source = cur->t->dstfmt;
00288    }
00289 
00290    AST_LIST_UNLOCK(&translators);
00291    return head;
00292 }

void ast_translator_deactivate ( struct ast_translator t  ) 

Deactivate a translator.

Parameters:
t translator to deactivate
Returns:
nothing
Disables the specified translator from being used.

Definition at line 780 of file translate.c.

References ast_translator::active, AST_LIST_LOCK, AST_LIST_UNLOCK, and rebuild_matrix().

00781 {
00782    AST_LIST_LOCK(&translators);
00783    t->active = 0;
00784    rebuild_matrix(0);
00785    AST_LIST_UNLOCK(&translators);
00786 }

void ast_translator_free_path ( struct ast_trans_pvt tr  ) 

Frees a translator path Frees the given translator path structure.

Parameters:
tr translator path to get rid of

Definition at line 245 of file translate.c.

References destroy(), and ast_trans_pvt::next.

00246 {
00247    struct ast_trans_pvt *pn = p;
00248    while ( (p = pn) ) {
00249       pn = p->next;
00250       destroy(p);
00251    }
00252 }

int ast_unregister_translator ( struct ast_translator t  ) 

Unregister a translator Unregisters the given tranlator.

Parameters:
t translator to unregister
Returns:
0 on success, -1 on failure

Definition at line 746 of file translate.c.

References ast_getformatname(), AST_LIST_LOCK, AST_LIST_REMOVE_CURRENT, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, AST_LIST_UNLOCK, ast_verbose(), COLOR_BLACK, COLOR_MAGENTA, ast_translator::dstfmt, ast_translator::name, option_verbose, rebuild_matrix(), ast_translator::srcfmt, term_color(), and VERBOSE_PREFIX_2.

00747 {
00748    char tmp[80];
00749    struct ast_translator *u;
00750    int found = 0;
00751 
00752    AST_LIST_LOCK(&translators);
00753    AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, u, list) {
00754       if (u == t) {
00755          AST_LIST_REMOVE_CURRENT(&translators, list);
00756          if (option_verbose > 1)
00757             ast_verbose(VERBOSE_PREFIX_2 "Unregistered translator '%s' from format %s to %s\n", term_color(tmp, t->name, COLOR_MAGENTA, COLOR_BLACK, sizeof(tmp)), ast_getformatname(1 << t->srcfmt), ast_getformatname(1 << t->dstfmt));
00758          found = 1;
00759          break;
00760       }
00761    }
00762    AST_LIST_TRAVERSE_SAFE_END;
00763 
00764    if (found)
00765       rebuild_matrix(0);
00766 
00767    AST_LIST_UNLOCK(&translators);
00768 
00769    return (u ? 0 : -1);
00770 }


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