Mercurial > SDL_sound_CoreAudio
view decoders/smpeg.c @ 466:75819e5c59d4
Build system fixes.
author | Ryan C. Gordon <icculus@icculus.org> |
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date | Wed, 15 Oct 2003 02:21:31 +0000 |
parents | 45614e2c1c81 |
children | c66080364dff 0f5888f9aef7 |
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/* * SDL_sound -- An abstract sound format decoding API. * Copyright (C) 2001 Ryan C. Gordon. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* * MPEG-1 Layer 3, or simply, "MP3", decoder for SDL_sound. * * This driver handles all those highly compressed songs you stole through * Napster. :) It depends on the SMPEG library for decoding, which can * be grabbed from: http://www.lokigames.com/development/smpeg.php3 * * This should also be able to extract the audio stream from an MPEG movie. * * There is an alternative MP3 decoder available, called "mpglib", which * doesn't depend on external libraries (the decoder itself is part of * SDL_sound), and may be more efficient, but less flexible than SMPEG. YMMV. * * Please see the file COPYING in the source's root directory. * * This file written by Ryan C. Gordon. (icculus@clutteredmind.org) */ #if HAVE_CONFIG_H # include <config.h> #endif #ifdef SOUND_SUPPORTS_SMPEG #include <stdio.h> #include <stdlib.h> #include <string.h> #include "SDL_sound.h" #define __SDL_SOUND_INTERNAL__ #include "SDL_sound_internal.h" #include "smpeg.h" #include "extra_rwops.h" static int _SMPEG_init(void); static void _SMPEG_quit(void); static int _SMPEG_open(Sound_Sample *sample, const char *ext); static void _SMPEG_close(Sound_Sample *sample); static Uint32 _SMPEG_read(Sound_Sample *sample); static int _SMPEG_rewind(Sound_Sample *sample); static int _SMPEG_seek(Sound_Sample *sample, Uint32 ms); static const char *extensions_smpeg[] = { "MP3", "MPEG", "MPG", NULL }; const Sound_DecoderFunctions __Sound_DecoderFunctions_SMPEG = { { extensions_smpeg, "MPEG-1 Layer 3 audio through SMPEG", "Ryan C. Gordon <icculus@clutteredmind.org>", "http://icculus.org/smpeg/" }, _SMPEG_init, /* init() method */ _SMPEG_quit, /* quit() method */ _SMPEG_open, /* open() method */ _SMPEG_close, /* close() method */ _SMPEG_read, /* read() method */ _SMPEG_rewind, /* rewind() method */ _SMPEG_seek /* seek() method */ }; static int _SMPEG_init(void) { return(1); /* always succeeds. */ } /* _SMPEG_init */ static void _SMPEG_quit(void) { /* it's a no-op. */ } /* _SMPEG_quit */ static __inline__ void output_version(void) { static int first_time = 1; if (first_time) { SMPEG_version v; SMPEG_VERSION(&v); SNDDBG(("SMPEG: Compiled against SMPEG v%d.%d.%d.\n", v.major, v.minor, v.patch)); first_time = 0; } /* if */ } /* output_version */ static int _SMPEG_open(Sound_Sample *sample, const char *ext) { SMPEG *smpeg; SMPEG_Info smpeg_info; SDL_AudioSpec spec; Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; SDL_RWops *refCounter; output_version(); /* * If I understand things correctly, MP3 files don't really have any * magic header we can check for. The MP3 player is expected to just * pick the first thing that looks like a valid frame and start * playing from there. * * So here's what we do: If the caller insists that this is really * MP3 we'll take his word for it. Otherwise, use the same test as * SDL_mixer does and check if the stream starts with something that * looks like a frame. * * A frame begins with 11 bits of frame sync (all bits must be set), * followed by a two-bit MPEG Audio version ID: * * 00 - MPEG Version 2.5 (later extension of MPEG 2) * 01 - reserved * 10 - MPEG Version 2 (ISO/IEC 13818-3) * 11 - MPEG Version 1 (ISO/IEC 11172-3) * * Apparently we don't handle MPEG Version 2.5. */ if (__Sound_strcasecmp(ext, "MP3") != 0) { Uint8 mp3_magic[2]; if (SDL_RWread(internal->rw, mp3_magic, sizeof (mp3_magic), 1) != 1) BAIL_MACRO("SMPEG: Could not read MP3 magic.", 0); if (mp3_magic[0] != 0xFF || (mp3_magic[1] & 0xF0) != 0xF0) BAIL_MACRO("SMPEG: Not an MP3 stream.", 0); /* If the seek fails, we'll probably miss a frame, but oh well */ SDL_RWseek(internal->rw, -sizeof (mp3_magic), SEEK_CUR); } /* if */ refCounter = RWops_RWRefCounter_new(internal->rw); if (refCounter == NULL) { SNDDBG(("SMPEG: Failed to create reference counting RWops.\n")); return(0); } /* if */ /* replace original RWops. This is safe. Honest. :) */ internal->rw = refCounter; /* * increment the refcount, since SMPEG will nuke the RWops if it can't * accept the contained data... */ RWops_RWRefCounter_addRef(refCounter); smpeg = SMPEG_new_rwops(refCounter, &smpeg_info, 0); if (SMPEG_error(smpeg)) { SMPEG_delete(smpeg); BAIL_MACRO(SMPEG_error(smpeg), 0); } /* if */ if (!smpeg_info.has_audio) { SMPEG_delete(smpeg); BAIL_MACRO("SMPEG: No audio stream found in data.", 0); } /* if */ SNDDBG(("SMPEG: Accepting data stream.\n")); SNDDBG(("SMPEG: has_audio == {%s}.\n", smpeg_info.has_audio ? "TRUE" : "FALSE")); SNDDBG(("SMPEG: has_video == {%s}.\n", smpeg_info.has_video ? "TRUE" : "FALSE")); SNDDBG(("SMPEG: width == (%d).\n", smpeg_info.width)); SNDDBG(("SMPEG: height == (%d).\n", smpeg_info.height)); SNDDBG(("SMPEG: current_frame == (%d).\n", smpeg_info.current_frame)); SNDDBG(("SMPEG: current_fps == (%f).\n", smpeg_info.current_fps)); SNDDBG(("SMPEG: audio_string == [%s].\n", smpeg_info.audio_string)); SNDDBG(("SMPEG: audio_current_frame == (%d).\n", smpeg_info.audio_current_frame)); SNDDBG(("SMPEG: current_offset == (%d).\n", smpeg_info.current_offset)); SNDDBG(("SMPEG: total_size == (%d).\n", smpeg_info.total_size)); SNDDBG(("SMPEG: current_time == (%f).\n", smpeg_info.current_time)); SNDDBG(("SMPEG: total_time == (%f).\n", smpeg_info.total_time)); SMPEG_enablevideo(smpeg, 0); SMPEG_enableaudio(smpeg, 1); SMPEG_loop(smpeg, 0); SMPEG_wantedSpec(smpeg, &spec); /* * One of the MP3s I tried wouldn't work unless I added this line * to tell SMPEG that yes, it may have the spec it wants. */ SMPEG_actualSpec(smpeg, &spec); sample->actual.format = spec.format; sample->actual.rate = spec.freq; sample->actual.channels = spec.channels; sample->flags = SOUND_SAMPLEFLAG_CANSEEK; internal->decoder_private = smpeg; SMPEG_play(smpeg); return(1); } /* _SMPEG_open */ static void _SMPEG_close(Sound_Sample *sample) { Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; SMPEG_delete((SMPEG *) internal->decoder_private); } /* _SMPEG_close */ static Uint32 _SMPEG_read(Sound_Sample *sample) { Uint32 retval; Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; SMPEG *smpeg = (SMPEG *) internal->decoder_private; /* * We have to clear the buffer because apparently SMPEG_playAudio() * will mix the decoded audio with whatever's already in it. Nasty. */ memset(internal->buffer, '\0', internal->buffer_size); retval = SMPEG_playAudio(smpeg, internal->buffer, internal->buffer_size); if (retval < internal->buffer_size) { char *errMsg = SMPEG_error(smpeg); if (errMsg == NULL) sample->flags |= SOUND_SAMPLEFLAG_EOF; else { __Sound_SetError(errMsg); sample->flags |= SOUND_SAMPLEFLAG_ERROR; } /* else */ } /* if */ return(retval); } /* _SMPEG_read */ static int _SMPEG_rewind(Sound_Sample *sample) { Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; SMPEG *smpeg = (SMPEG *) internal->decoder_private; SMPEGstatus status; /* * SMPEG_rewind() really means "stop and rewind", so we may have to * restart it afterwards. */ status = SMPEG_status(smpeg); SMPEG_rewind(smpeg); /* EW: I think SMPEG_play() has an independent and unrelated meaning * to the flag, "SMPEG_PLAYING". This is why the SMPEG_play() call * is done in the open() function even though the file is not yet * technically playing. I believe SMPEG_play() must always be active * because this seems to be what's causing the: * "Can't rewind after the file has finished playing once" problem, * because always recalling it here seems to make the problem go away. */ /* if (status == SMPEG_PLAYING) SMPEG_play(smpeg); */ SMPEG_play(smpeg); return(1); } /* _SMPEG_rewind */ static int _SMPEG_seek(Sound_Sample *sample, Uint32 ms) { Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; SMPEG *smpeg = (SMPEG *) internal->decoder_private; SMPEGstatus status; /* * SMPEG_rewind() really means "stop and rewind", so we may have to * restart it afterwards. */ status = SMPEG_status(smpeg); SMPEG_rewind(smpeg); SMPEG_skip(smpeg, ((float) ms) / 1000.0); if (status == SMPEG_PLAYING) SMPEG_play(smpeg); return(1); } /* _SMPEG_seek */ #endif /* SOUND_SUPPORTS_SMPEG */ /* end of smpeg.c ... */