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author | Justin Ruggles <justin.ruggles@gmail.com> | 2011-11-19 17:46:15 -0500 |
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committer | Justin Ruggles <justin.ruggles@gmail.com> | 2011-11-26 16:25:06 -0500 |
commit | 8db67610c016d1aa8ed09643b1ee9b96f7b18c01 (patch) | |
tree | 29d88dbe07906d3166cd21b009b6066a344690b0 /libavcodec | |
parent | fbc79a9101b9674327beba9c2a454163ead1e7a5 (diff) | |
download | ffmpeg-8db67610c016d1aa8ed09643b1ee9b96f7b18c01.tar.gz |
adx: cosmetics: general pretty-printing and comment clean-up
Diffstat (limited to 'libavcodec')
-rw-r--r-- | libavcodec/adxdec.c | 134 |
1 files changed, 73 insertions, 61 deletions
diff --git a/libavcodec/adxdec.c b/libavcodec/adxdec.c index 642d31dd66..7d06d27a75 100644 --- a/libavcodec/adxdec.c +++ b/libavcodec/adxdec.c @@ -38,82 +38,95 @@ static av_cold int adx_decode_init(AVCodecContext *avctx) return 0; } -/* 18 bytes <-> 32 samples */ - -static void adx_decode(int16_t *out,const unsigned char *in, - ADXChannelState *prev) +/** + * Decode 32 samples from 18 bytes. + * + * A 16-bit scalar value is applied to 32 residuals, which then have a + * 2nd-order LPC filter applied to it to form the output signal for a single + * channel. + */ +static void adx_decode(int16_t *out, const uint8_t *in, ADXChannelState *prev) { int scale = AV_RB16(in); int i; - int s0,s1,s2,d; + int s0, s1, s2, d; - in+=2; + in += 2; s1 = prev->s1; s2 = prev->s2; - for(i=0;i<16;i++) { - d = in[i]; - d = ((signed char)d >> 4); - s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14; + for (i = 0; i < 16; i++) { + d = in[i]; + d = (signed char)d >> 4; + s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14; s2 = s1; s1 = av_clip_int16(s0); - *out++=s1; + *out++ = s1; - d = in[i]; - d = ((signed char)(d<<4) >> 4); - s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14; + d = in[i]; + d = (signed char)(d << 4) >> 4; + s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14; s2 = s1; s1 = av_clip_int16(s0); - *out++=s1; + *out++ = s1; } prev->s1 = s1; prev->s2 = s2; - } -static void adx_decode_stereo(int16_t *out,const unsigned char *in, +static void adx_decode_stereo(int16_t *out,const uint8_t *in, ADXChannelState *prev) { short tmp[32*2]; int i; - adx_decode(tmp ,in ,prev); - adx_decode(tmp+32,in+18,prev+1); - for(i=0;i<32;i++) { - out[i*2] = tmp[i]; + adx_decode(tmp, in, prev); + adx_decode(tmp+32, in+18, prev+1); + for (i = 0; i < 32; i++) { + out[i*2 ] = tmp[i ]; out[i*2+1] = tmp[i+32]; } } -/* return data offset or 0 */ -static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize) +/** + * Decode stream header. + * + * @param avctx codec context + * @param buf packet data + * @param bufsize packet size + * @return data offset or 0 if header is invalid + */ +static int adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, + int bufsize) { int offset; - if (buf[0]!=0x80) return 0; - offset = (AV_RB32(buf)^0x80000000)+4; - if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0; + if (buf[0] != 0x80) + return 0; + offset = (AV_RB32(buf) ^ 0x80000000) + 4; + if (bufsize < offset || memcmp(buf + offset - 6, "(c)CRI", 6)) + return 0; avctx->channels = buf[7]; - avctx->sample_rate = AV_RB32(buf+8); - avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32; + avctx->sample_rate = AV_RB32(buf + 8); + avctx->bit_rate = avctx->sample_rate * avctx->channels * 18 * 8 / 32; return offset; } -static int adx_decode_frame(AVCodecContext *avctx, - void *data, int *data_size, - AVPacket *avpkt) +static int adx_decode_frame(AVCodecContext *avctx, void *data, int *data_size, + AVPacket *avpkt) { const uint8_t *buf0 = avpkt->data; - int buf_size = avpkt->size; - ADXContext *c = avctx->priv_data; - int16_t *samples = data; - const uint8_t *buf = buf0; - int rest = buf_size; + int buf_size = avpkt->size; + ADXContext *c = avctx->priv_data; + int16_t *samples = data; + const uint8_t *buf = buf0; + int rest = buf_size; if (!c->header_parsed) { - int hdrsize = adx_decode_header(avctx,buf,rest); - if (hdrsize==0) return -1; + int hdrsize = adx_decode_header(avctx, buf, rest); + if (!hdrsize) + return -1; c->header_parsed = 1; buf += hdrsize; rest -= hdrsize; @@ -121,46 +134,46 @@ static int adx_decode_frame(AVCodecContext *avctx, /* 18 bytes of data are expanded into 32*2 bytes of audio, so guard against buffer overflows */ - if(rest/18 > *data_size/64) - rest = (*data_size/64) * 18; + if (rest / 18 > *data_size / 64) + rest = (*data_size / 64) * 18; if (c->in_temp) { - int copysize = 18*avctx->channels - c->in_temp; - memcpy(c->dec_temp+c->in_temp,buf,copysize); + int copysize = 18 * avctx->channels - c->in_temp; + memcpy(c->dec_temp + c->in_temp, buf, copysize); rest -= copysize; buf += copysize; - if (avctx->channels==1) { - adx_decode(samples,c->dec_temp,c->prev); + if (avctx->channels == 1) { + adx_decode(samples, c->dec_temp, c->prev); samples += 32; } else { - adx_decode_stereo(samples,c->dec_temp,c->prev); + adx_decode_stereo(samples, c->dec_temp, c->prev); samples += 32*2; } } - if (avctx->channels==1) { - while(rest>=18) { - adx_decode(samples,buf,c->prev); - rest-=18; - buf+=18; - samples+=32; + if (avctx->channels == 1) { + while (rest >= 18) { + adx_decode(samples, buf, c->prev); + rest -= 18; + buf += 18; + samples += 32; } } else { - while(rest>=18*2) { - adx_decode_stereo(samples,buf,c->prev); - rest-=18*2; - buf+=18*2; - samples+=32*2; + while (rest >= 18 * 2) { + adx_decode_stereo(samples, buf, c->prev); + rest -= 18 * 2; + buf += 18 * 2; + samples += 32 * 2; } } c->in_temp = rest; if (rest) { - memcpy(c->dec_temp,buf,rest); - buf+=rest; + memcpy(c->dec_temp, buf, rest); + buf += rest; } *data_size = (uint8_t*)samples - (uint8_t*)data; - return buf-buf0; + return buf - buf0; } AVCodec ff_adpcm_adx_decoder = { @@ -170,6 +183,5 @@ AVCodec ff_adpcm_adx_decoder = { .priv_data_size = sizeof(ADXContext), .init = adx_decode_init, .decode = adx_decode_frame, - .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), + .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), }; - |