From cc11e9466a3aa2ffc67779f80b2059a326301660 Mon Sep 17 00:00:00 2001 From: Andree Buschmann Date: Wed, 4 Jun 2008 05:41:59 +0000 Subject: Further changes in mpc buffered seek. Remove magical number and replace it with a better commented #define. Use shift and bit mask instead of division and modulo operations when using the seek buffer. Saves some binary size for the codec. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17686 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/libmusepack/mpc_decoder.c | 46 ++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 20 deletions(-) (limited to 'apps/codecs/libmusepack/mpc_decoder.c') diff --git a/apps/codecs/libmusepack/mpc_decoder.c b/apps/codecs/libmusepack/mpc_decoder.c index 75dd1da918..e63d1efaec 100644 --- a/apps/codecs/libmusepack/mpc_decoder.c +++ b/apps/codecs/libmusepack/mpc_decoder.c @@ -96,6 +96,7 @@ mpc_uint8_t LUTDSCF [1<< 6] IBSS_ATTR_MPC_LARGE_IRAM; // 64 Bytes = 2976 B //------------------------------------------------------------------------------ enum { + SEEK_PRE_DECODE = 33, // number of frames to be pre-decoded MEMSIZE = MPC_DECODER_MEMSIZE, // overall buffer size MEMSIZE2 = (MEMSIZE/2), // size of one buffer MEMMASK = (MEMSIZE-1) @@ -502,9 +503,9 @@ mpc_decoder_decode_internal(mpc_decoder *d, MPC_SAMPLE_FORMAT *buffer) /* update seek table */ d->SeekTableCounter += d->FwdJumpInfo + 20; - if (0 == (d->DecodedFrames % d->SeekTable_Step)) + if (0 == ((d->DecodedFrames) & (d->SeekTable_Mask))) { - d->SeekTable[d->DecodedFrames/d->SeekTable_Step] = d->SeekTableCounter; + d->SeekTable[d->DecodedFrames>>d->SeekTable_Step] = d->SeekTableCounter; d->MaxDecodedFrames = d->DecodedFrames; d->SeekTableCounter = 0; } @@ -1435,7 +1436,8 @@ void mpc_decoder_setup(mpc_decoder *d, mpc_reader *r) d->Ring = 0; d->WordsRead = 0; d->Max_Band = 0; - d->SeekTable_Step = 1; + d->SeekTable_Step = 0; + d->SeekTable_Mask = 0; d->SeekTableCounter = 0; mpc_decoder_initialisiere_quantisierungstabellen(d, 1.0f); @@ -1488,7 +1490,11 @@ static void mpc_decoder_set_streaminfo(mpc_decoder *d, mpc_streaminfo *si) // limit used table size to MPC_SEEK_BUFFER_SIZE seekTableSize = min(si->frames, MPC_SEEK_BUFFER_SIZE); // frames per buffer to not exceed buffer and to be able to seek full file - d->SeekTable_Step = (si->frames + seekTableSize - 1) / seekTableSize; + while ( seekTableSize < si->frames / (1<SeekTable_Step) ) + { + d->SeekTable_Step++; + } + d->SeekTable_Mask = (1 << d->SeekTable_Step) - 1; } mpc_bool_t mpc_decoder_initialize(mpc_decoder *d, mpc_streaminfo *si) @@ -1595,8 +1601,8 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) // seek direction (note: avoids casting to int64) delta = (d->DecodedFrames > seekFrame ? -(mpc_int32_t)(d->DecodedFrames - seekFrame) : (mpc_int32_t)(seekFrame - d->DecodedFrames)); - if (seekFrame > 33) - lastFrame = seekFrame - 33 + 1 - d->SeekTable_Step; + if (seekFrame > SEEK_PRE_DECODE) + lastFrame = seekFrame - SEEK_PRE_DECODE + 1 - (1<SeekTable_Step); if (d->MaxDecodedFrames == 0) // nothing decoded yet, parse stream { @@ -1614,9 +1620,9 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) for (d->DecodedFrames = 0; d->DecodedFrames < lastFrame; d->DecodedFrames++) { d->SeekTableCounter += mpc_decoder_jump_frame(d); - if (0 == ((d->DecodedFrames+1) % d->SeekTable_Step)) + if (0 == ((d->DecodedFrames+1) & (d->SeekTable_Mask))) { - d->SeekTable[(d->DecodedFrames+1)/d->SeekTable_Step] = d->SeekTableCounter; + d->SeekTable[(d->DecodedFrames+1)>>d->SeekTable_Step] = d->SeekTableCounter; d->MaxDecodedFrames = d->DecodedFrames; d->SeekTableCounter = 0; } @@ -1630,15 +1636,15 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) fpos = d->SeekTable[0]; for (d->DecodedFrames = 0; d->DecodedFrames < lastFrame; d->DecodedFrames++) { - if (0 == (d->DecodedFrames+1) % d->SeekTable_Step) + if (0 == ((d->DecodedFrames+1) & (d->SeekTable_Mask))) { - fpos += d->SeekTable[(d->DecodedFrames+1)/d->SeekTable_Step]; + fpos += d->SeekTable[(d->DecodedFrames+1)>>d->SeekTable_Step]; d->SeekTableCounter = 0; } } mpc_decoder_seek_to(d, fpos); } - else if (delta > 33) // jump forward, seek table is available + else if (delta > SEEK_PRE_DECODE) // jump forward, seek table is available { mpc_decoder_reset_state(d); @@ -1646,9 +1652,9 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) fpos = mpc_decoder_bits_read(d); for (; d->DecodedFrames < d->MaxDecodedFrames && d->DecodedFrames < lastFrame; d->DecodedFrames++) { - if (0 == (d->DecodedFrames+1) % d->SeekTable_Step) + if (0 == ((d->DecodedFrames+1) & (d->SeekTable_Mask))) { - fpos += d->SeekTable[(d->DecodedFrames+1)/d->SeekTable_Step]; + fpos += d->SeekTable[(d->DecodedFrames+1)>>d->SeekTable_Step]; d->SeekTableCounter = 0; } } @@ -1658,18 +1664,18 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) for (;d->DecodedFrames < lastFrame; d->DecodedFrames++) { d->SeekTableCounter += mpc_decoder_jump_frame(d); - if (0 == (d->DecodedFrames+1) % d->SeekTable_Step) + if (0 == ((d->DecodedFrames+1) & (d->SeekTable_Mask))) { - d->SeekTable[(d->DecodedFrames+1)/d->SeekTable_Step] = d->SeekTableCounter; + d->SeekTable[(d->DecodedFrames+1)>>d->SeekTable_Step] = d->SeekTableCounter; d->MaxDecodedFrames = d->DecodedFrames; d->SeekTableCounter = 0; } } } - // until here we jumped to desired position -33 frames + // until here we jumped to desired position -SEEK_PRE_DECODE frames - // now we decode the last 33 frames until we reach the seek position - // this is neccessary as mpc uses entropy coding in time domain + // now we decode the last SEEK_PRE_DECODE frames until we reach the seek + // position. this is neccessary as mpc uses entropy coding in time domain for (;d->DecodedFrames < seekFrame; d->DecodedFrames++) { mpc_uint32_t FrameBitCnt; @@ -1701,9 +1707,9 @@ mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample) // update seek table, if there new entries to fill d->SeekTableCounter += d->FwdJumpInfo + 20; - if (0 == (d->DecodedFrames+1) % d->SeekTable_Step) + if (0 == ((d->DecodedFrames+1) & (d->SeekTable_Mask))) { - d->SeekTable[(d->DecodedFrames+1)/d->SeekTable_Step] = d->SeekTableCounter; + d->SeekTable[(d->DecodedFrames+1)>>d->SeekTable_Step] = d->SeekTableCounter; d->MaxDecodedFrames = d->DecodedFrames; d->SeekTableCounter = 0; } -- cgit v1.2.3