Changeset 146

Timestamp:

11/18/06 18:46:21 (18 years ago)

Author:

r2d

Message:

• added seek table

Location:

libmpc/branches/r2d/libmpcdec

Files:

• internal.h (modified) (1 diff)
• mpc_demux.c (modified) (7 diffs)
• streaminfo.c (modified) (2 diffs)

libmpc/branches/r2d/libmpcdec/internal.h

@@ -69 +69 @@
         mpc_decoder * d;
         mpc_streaminfo si;
+
+        // buffer
         mpc_uint8_t buffer[DEMUX_BUFFER_SIZE];
-        mpc_uint32_t bytes_total;
+        mpc_size_t bytes_total;
         mpc_bits_reader bits_reader;
         mpc_uint32_t block_bits; /// bits remaining in current audio block
         mpc_bool_t end; /// end of stream flag
+
+        // seeking
+        mpc_uint32_t * seek_table;
+        mpc_uint_t seek_pwr; /// distance between 2 frames in seek_table = 2^seek_pwr
+        mpc_uint32_t seek_table_size; /// used size in seek_table
 };
 

libmpc/branches/r2d/libmpcdec/mpc_demux.c

@@ -107 +107 @@
 /**
  * seek to a bit position in the stream
- * @param d
+ * @param d demuxer context
  * @param fpos position in the stream in bits from the beginning of mpc datas
  * @param min_bytes number of bytes to load after seeking
@@ -133 +133 @@
         d->bits_reader.buff += bit_offset >> 3;
         d->bits_reader.count = 8 - (bit_offset & 7);
+}
+
+/**
+ * return the current position in the stream (in bits)
+ * @param d demuxer context
+ * @return current stream position in bits
+ */
+static mpc_size_t mpc_demux_pos(mpc_demux * d)
+{
+        return ((d->r->tell(d->r) - d->bytes_total + d->bits_reader.buff - d->buffer) << 3) + 8 - d->bits_reader.count;
 }
 
@@ -198 +208 @@
                 p_tmp->r = p_reader;
                 mpc_demux_clear_buff(p_tmp);
-                // lire entête
                 if (mpc_demux_header(p_tmp) == MPC_STATUS_OK) {
-                        // initialisation decodeur
+                        p_tmp->seek_pwr = 6;
+                        if (p_tmp->si.block_pwr > p_tmp->seek_pwr)
+                                p_tmp->seek_pwr = p_tmp->si.block_pwr;
+                        p_tmp->seek_table = malloc((1 + p_tmp->si.samples / (MPC_FRAME_LENGTH << p_tmp->seek_pwr)) * sizeof(mpc_uint32_t));
+                        p_tmp->seek_table[0] = mpc_demux_pos(p_tmp);
+                        p_tmp->seek_table_size = 1;
                         p_tmp->d = mpc_decoder_init(&p_tmp->si);
                 } else {
@@ -214 +228 @@
 {
         mpc_decoder_exit(d->d);
+        free(d->seek_table);
         free(d);
 }
@@ -222 +237 @@
 }
 
+#include <stdio.h>
+
 void mpc_demux_decode(mpc_demux * d, mpc_frame_info * i)
 {
+        if (d->d->decoded_samples == (d->seek_table_size << d->seek_pwr) * MPC_FRAME_LENGTH) {
+                d->seek_table[d->seek_table_size] = mpc_demux_pos(d);
+                d->seek_table_size ++;
+        }
+
         if (d->si.stream_version >= 8) {
                 mpc_bits_reader r;
@@ -263 +285 @@
 mpc_status mpc_demux_seek_sample(mpc_demux * d, mpc_int64_t destsample)
 {
-        mpc_uint32_t fwd, samples_to_skip, fpos = 32, i;
+        mpc_uint32_t fwd, samples_to_skip, fpos, i;
+        mpc_uint32_t block_samples = MPC_FRAME_LENGTH << d->si.block_pwr;
 
         if (destsample > d->si.samples) destsample = d->si.samples;
-        fwd = (mpc_uint32_t) (destsample / (MPC_FRAME_LENGTH * d->si.frames_per_block));
-        samples_to_skip = MPC_DECODER_SYNTH_DELAY + (mpc_uint32_t)
-                        (destsample % (MPC_FRAME_LENGTH * d->si.frames_per_block));
-
-        // FIXME : we start seeking from the beginning of the file, easier but not optimal
-        d->d->decoded_samples = 0;
-
-        if (d->si.stream_version >= 8) {
-                mpc_block b;
-                int size;
-                mpc_demux_seek(d, fpos, 11);
-                size = mpc_bits_get_block(&d->bits_reader, &b);
-                for( i = 0; i < fwd; ){
-                        if (memcmp(b.key, "AD", 2) == 0){
-                                i++;
-                                d->d->decoded_samples += MPC_FRAME_LENGTH * d->si.frames_per_block;
-                        }
-                        fpos += (b.size + size) * 8;
-                        mpc_demux_seek(d, fpos, 11);
-                        size = mpc_bits_get_block(&d->bits_reader, &b);
-                }
-                d->bits_reader.buff -= size;
-        } else {
+        fwd = (mpc_uint32_t) (destsample / block_samples);
+        samples_to_skip = MPC_DECODER_SYNTH_DELAY +
+                        (mpc_uint32_t) (destsample % block_samples);
+        if (d->si.stream_version == 7) {
                 if (fwd > 32) {
                         fwd -= 32;
@@ -296 +300 @@
                         fwd = 0;
                 }
+        }
+
+        i = fwd >> (d->seek_pwr - d->si.block_pwr);
+        if (i >= d->seek_table_size)
+                i = d->seek_table_size - 1;
+        fpos = d->seek_table[i];
+        i <<= d->seek_pwr - d->si.block_pwr;
+        d->d->decoded_samples = i * block_samples;
+
+        if (d->si.stream_version >= 8) {
+                mpc_block b;
+                int size;
+                mpc_demux_seek(d, fpos, 11);
+                size = mpc_bits_get_block(&d->bits_reader, &b);
+                while(i < fwd) {
+                        if (memcmp(b.key, "AD", 2) == 0) {
+                                if (d->d->decoded_samples == (d->seek_table_size << d->seek_pwr) * MPC_FRAME_LENGTH) {
+                                        d->seek_table[d->seek_table_size] = mpc_demux_pos(d) - 8 * size;
+                                        d->seek_table_size ++;
+                                }
+                                d->d->decoded_samples += block_samples;
+                                i++;
+                        }
+                        fpos += (b.size + size) * 8;
+                        mpc_demux_seek(d, fpos, 11);
+                        size = mpc_bits_get_block(&d->bits_reader, &b);
+                }
+                d->bits_reader.buff -= size;
+        } else {
                 mpc_decoder_reset_scf(d->d);
-                fpos += 21 * 8;
                 mpc_demux_seek(d, fpos, 4);
-                for( i = 0; i < fwd; i++){
+                for( ; i < fwd; i++){
+                        if (d->d->decoded_samples == (d->seek_table_size << d->seek_pwr) * MPC_FRAME_LENGTH) {
+                                d->seek_table[d->seek_table_size] = mpc_demux_pos(d);
+                                d->seek_table_size ++;
+                        }
+                        d->d->decoded_samples += block_samples;
                         fpos += mpc_bits_read(&d->bits_reader, 20) + 20;
                         mpc_demux_seek(d, fpos, 4);
-                        d->d->decoded_samples += MPC_FRAME_LENGTH;
                 }
         }

libmpc/branches/r2d/libmpcdec/streaminfo.c

@@ -123 +123 @@
         si->encoder_version    = mpc_bits_read(r, 8);
     si->channels           = 2;
-        si->frames_per_block   = 1;
+        si->block_pwr          = 0;
 
         mpc_get_encoder_string(si);
@@ -160 +160 @@
         si->max_band = mpc_bits_read(&r, 5) + 1;
         si->ms = mpc_bits_read(&r, 1);
-        si->frames_per_block = 1 << mpc_bits_read(&r, 4);
+        si->block_pwr = mpc_bits_read(&r, 4);
 
         si->bitrate = 0;