Mercurial > SDL_sound_CoreAudio
diff decoders/wav.c @ 333:565ae12fa74e
Implemented seek support for ADPCM-compressed WAVs.
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Mon, 20 May 2002 11:19:50 +0000 |
parents | eb7c929193dd |
children | 069ce624d6cf |
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--- a/decoders/wav.c Mon May 20 09:41:38 2002 +0000 +++ b/decoders/wav.c Mon May 20 11:19:50 2002 +0000 @@ -527,7 +527,45 @@ static int seek_sample_fmt_adpcm(Sound_Sample *sample, Uint32 ms) { - return(0); /* !!! FIXME: Can we reasonably implement this? */ + Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque; + wav_t *w = (wav_t *) internal->decoder_private; + fmt_t *fmt = w->fmt; + Uint32 origsampsleft = fmt->fmt.adpcm.samples_left_in_block; + int origpos = SDL_RWtell(internal->rw); + int offset = __Sound_convertMsToBytePos(&sample->actual, ms); + int bpb = (fmt->fmt.adpcm.wSamplesPerBlock * fmt->sample_frame_size); + int skipsize = (offset / bpb) * fmt->wBlockAlign; + int pos = skipsize + fmt->data_starting_offset; + int rc = SDL_RWseek(internal->rw, pos, SEEK_SET); + BAIL_IF_MACRO(rc != pos, ERR_IO_ERROR, 0); + + /* The offset we need is in this block, so we need to decode to there. */ + skipsize += (offset % bpb); + rc = (offset % bpb); /* bytes into this block we need to decode */ + if (!read_adpcm_block_headers(sample)) + { + SDL_RWseek(internal->rw, origpos, SEEK_SET); /* try to make sane. */ + return(0); + } /* if */ + + /* first sample frame of block is a freebie. :) */ + fmt->fmt.adpcm.samples_left_in_block--; + rc -= fmt->sample_frame_size; + while (rc > 0) + { + if (!decode_adpcm_sample_frame(sample)) + { + SDL_RWseek(internal->rw, origpos, SEEK_SET); + fmt->fmt.adpcm.samples_left_in_block = origsampsleft; + return(0); + } /* if */ + + fmt->fmt.adpcm.samples_left_in_block--; + rc -= fmt->sample_frame_size; + } /* while */ + + w->bytesLeft = fmt->total_bytes - skipsize; + return(1); /* success. */ } /* seek_sample_fmt_adpcm */ @@ -544,6 +582,7 @@ fmt->free = free_fmt_adpcm; fmt->read_sample = read_sample_fmt_adpcm; fmt->rewind_sample = rewind_sample_fmt_adpcm; + fmt->seek_sample = seek_sample_fmt_adpcm; BAIL_IF_MACRO(!read_le16(rw, &fmt->fmt.adpcm.cbSize), NULL, 0); BAIL_IF_MACRO(!read_le16(rw, &fmt->fmt.adpcm.wSamplesPerBlock), NULL, 0); @@ -677,15 +716,13 @@ w->fmt = fmt; fmt->total_bytes = w->bytesLeft = d.chunkSize; fmt->data_starting_offset = SDL_RWtell(rw); - - /* !!! FIXME: Move this to Sound_SampleInfo ? */ fmt->sample_frame_size = ( ((sample->actual.format & 0xFF) / 8) * sample->actual.channels ); internal->decoder_private = (void *) w; sample->flags = SOUND_SAMPLEFLAG_NONE; - if (fmt->wFormatTag == FMT_NORMAL) + if (fmt->seek_sample != NULL) sample->flags |= SOUND_SAMPLEFLAG_CANSEEK; SNDDBG(("WAV: Accepting data stream.\n"));