Mercurial > SDL_sound_CoreAudio

comparison decoders/raw.c @ 474:c66080364dff

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Most decoders now report total sample play time, now. Technically, this breaks binary compatibility with the 1.0 branch, since it extends the Sound_Sample struct, but most (all?) programs are just passing pointers allocated by SDL_sound around, and might be okay. Source-level compatibility is not broken...yet! :) --ryan. -------- Original Message -------- Subject: SDL_sound patch: Finding total length of time of sound file. Date: Sun, 26 Jan 2003 09:31:17 -0800 (PST) Hi Ryan, I am working with Eric Wing and helping him modify SDL_sound. AS part of our efforts in improving and enhancing SDL_sound, we like to submit this patch. We modified the codecs to find the total time of a sound file. Below is the explanation of the patch. The patch is appended as an attachment to this email. * MOTIVATION: We needed the ability to get the total play time of a sample (And we noticed that we're not the only ones). Since SDL_sound blocks direct access to the specific decoders, there is no way for a user to know this information short of decoding the whole thing. Because of this, we believe this will be a useful addition, even though the accuracy may not be perfect (subject to each decoder) or the information may not always be available. * CONTRIBUTORS: Wesley Leong (modified the majority of the codecs and verified the results) Eric Wing (showed everyone how to do modify codec, modified mikmod) Wang Lam (modified a handful of codecs, researched into specs and int overflow) Ahilan Anantha (modified a few codecs and helped with integer math) * GENERAL ISSUES: We chose the value to be milliseconds as an Sint32. Milliseconds because that's what Sound_Seek takes as a parameter and -1 to allow for instances/codecs where the value could not be determined. We are not sure if this is the final convention you want, so we are willing to work with you on this. We also expect the total_time field to be set on open and never again modified by SDL_sound. Users may access it directly much like the sample buffer and buffer_size. We thought about recomputing the time on DecodeAll, but since users may seek or decode small chunks first, not all the data may be there. So this is better done by the user. This may be good information to document. Currently, all the main codecs are implemented except for QuickTime.
author Ryan C. Gordon <icculus@icculus.org>
date Sat, 08 May 2004 08:19:50 +0000
parents fb519e6028e3
children 3e705c9180e5
comparison
equal deleted inserted replaced
473:1edb89260487 474:c66080364dff
93 } /* RAW_quit */ 93 } /* RAW_quit */
94 94
95 95
96 static int RAW_open(Sound_Sample *sample, const char *ext) 96 static int RAW_open(Sound_Sample *sample, const char *ext)
97 { 97 {
98 Sound_SampleInternal *internal = sample->opaque;
99 SDL_RWops *rw = internal->rw;
100 Uint32 pos, sample_rate;
101
98 /* 102 /*
99 * We check this explicitly, since we have no other way to 103 * We check this explicitly, since we have no other way to
100 * determine whether we should handle this data or not. 104 * determine whether we should handle this data or not.
101 */ 105 */
102 if (__Sound_strcasecmp(ext, "RAW") != 0) 106 if (__Sound_strcasecmp(ext, "RAW") != 0)
120 * We never convert raw samples; what you ask for is what you get. 124 * We never convert raw samples; what you ask for is what you get.
121 */ 125 */
122 memcpy(&sample->actual, &sample->desired, sizeof (Sound_AudioInfo)); 126 memcpy(&sample->actual, &sample->desired, sizeof (Sound_AudioInfo));
123 sample->flags = SOUND_SAMPLEFLAG_CANSEEK; 127 sample->flags = SOUND_SAMPLEFLAG_CANSEEK;
124 128
129 if ( (pos = SDL_RWseek(internal->rw, 0, SEEK_END) ) <= 0) {
130 BAIL_MACRO("RAW: cannot seek the end of the file \"RAW\".", 0);
131 }
132 if ( SDL_RWseek(internal->rw, 0, SEEK_SET) ) {
133 BAIL_MACRO("RAW: cannot reset file \"RAW\".", 0);
134 }
135
136 sample_rate = (sample->actual.rate * sample->actual.channels
137 * ( (sample->actual.format & 0x0018) >> 3) );
138 sample->total_time = ( pos ) / sample_rate * 1000;
139 sample->total_time += (pos % sample_rate) * 1000 / sample_rate;
140
125 return(1); /* we'll handle this data. */ 141 return(1); /* we'll handle this data. */
126 } /* RAW_open */ 142 } /* RAW_open */
127 143
128 144
129 static void RAW_close(Sound_Sample *sample) 145 static void RAW_close(Sound_Sample *sample)