Changeset 143 for libmpc/branches/r2d/libmpcdec/mpc_demux.c

Timestamp:

11/17/06 21:04:35 (18 years ago)

Author:

r2d

Message:

• added simple seeking for sv7 and sv8

File:

• libmpc/branches/r2d/libmpcdec/mpc_demux.c (modified) (6 diffs)

libmpc/branches/r2d/libmpcdec/mpc_demux.c

@@ -53 +53 @@
 
 enum {
-        MPC_BUFFER_CLEAR = 1,
-        MPC_BUFFER_SWAP = 2,
-        MPC_BUFFER_FULL = 4,
+        MPC_BUFFER_SWAP = 1,
+        MPC_BUFFER_FULL = 2,
 };
+
+static void mpc_demux_clear_buff(mpc_demux * d)
+{
+        d->bytes_total = 0;
+        d->bits_reader.buff = d->buffer;
+        d->bits_reader.count = 8;
+        d->block_bits = 0;
+        d->end = MPC_FALSE;
+}
 
 static mpc_uint32_t
@@ -95 +103 @@
 
         return 0;
+}
+
+/**
+ * seek to a bit position in the stream
+ * @param d
+ * @param fpos position in the stream in bits from the beginning of mpc datas
+ * @param min_bytes number of bytes to load after seeking
+ */
+static void
+mpc_demux_seek(mpc_demux * d, mpc_uint32_t fpos, mpc_uint32_t min_bytes) {
+//      mpc_uint32_t cur_pos = d->r->tell(d->r);
+        mpc_uint32_t next_pos;
+        mpc_int_t bit_offset;
+
+        // FIXME : do not flush the buffer if fpos is in the current buffer
+
+        next_pos = fpos >> 3;
+        if (d->si.stream_version == 7)
+                next_pos &= (-1u << 2);
+        bit_offset = fpos - (next_pos << 3);
+        next_pos += d->si.header_position; // add id3 offset
+
+        d->r->seek(d->r, next_pos);
+        mpc_demux_clear_buff(d);
+        if (d->si.stream_version == 7)
+                mpc_demux_fill(d, (min_bytes + ((bit_offset + 7) >> 3) + 3) & (-1 << 2), MPC_BUFFER_SWAP);
+        else
+                mpc_demux_fill(d, min_bytes + ((bit_offset + 7) >> 3), 0);
+        d->bits_reader.buff += bit_offset >> 3;
+        d->bits_reader.count = 8 - (bit_offset & 7);
 }
 
@@ -159 +197 @@
         if (p_tmp != 0) {
                 p_tmp->r = p_reader;
-                p_tmp->bytes_total = 0;
-                p_tmp->bits_reader.buff = p_tmp->buffer;
-                p_tmp->bits_reader.count = 8;
-                p_tmp->block_bits = 0;
-                p_tmp->end = MPC_FALSE;
+                mpc_demux_clear_buff(p_tmp);
                 // lire entête
                 if (mpc_demux_header(p_tmp) == MPC_STATUS_OK) {
@@ -190 +224 @@
 void mpc_demux_decode(mpc_demux * d, mpc_frame_info * i)
 {
-        if (d->si.stream_version == 8) {
+        if (d->si.stream_version >= 8) {
                 mpc_bits_reader r;
-                if (d->block_bits < 8 && d->end == MPC_FALSE){
+                if (d->block_bits < 8 && d->end == MPC_FALSE) {
                         mpc_block b;
                         d->bits_reader.count &= -8;
                         mpc_demux_fill(d, 11, 0); // max header block size
                         mpc_bits_get_block(&d->bits_reader, &b);
-                        while( memcmp(b.key, "AD", 2) != 0 ){ // scan all blocks until audio
-                                if (memcmp(b.key, "SE", 2) == 0) // end block
+                        while( memcmp(b.key, "AD", 2) != 0 ) { // scan all blocks until audio
+                                if (memcmp(b.key, "SE", 2) == 0) { // end block
                                         d->end = MPC_TRUE;
+                                        break;
+                                }
                                 mpc_demux_fill(d, 11 + b.size, 0);
                                 d->bits_reader.buff += b.size;
@@ -206 +242 @@
                         d->block_bits = b.size * 8;
                 }
-
+                // FIXME : this is not good if block size > buffer size
                 mpc_demux_fill(d, (d->block_bits >> 3) + 1, 0);
                 r = d->bits_reader;
@@ -220 +256 @@
 }
 
+mpc_status mpc_demux_seek_second(mpc_demux * d, double seconds)
+{
+        return mpc_demux_seek_sample(d, (mpc_int64_t)(seconds * (double)d->si.sample_freq + 0.5));
+}
+
+mpc_status mpc_demux_seek_sample(mpc_demux * d, mpc_int64_t destsample)
+{
+        mpc_uint32_t fwd, samples_to_skip, fpos = 32, i;
+
+        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 {
+                if (fwd > 32) {
+                        fwd -= 32;
+                        samples_to_skip += MPC_FRAME_LENGTH * 32;
+                } else {
+                        samples_to_skip += MPC_FRAME_LENGTH * fwd;
+                        fwd = 0;
+                }
+                mpc_decoder_reset_scf(d->d);
+                fpos += 21 * 8;
+                mpc_demux_seek(d, fpos, 4);
+                for( i = 0; i < fwd; i++){
+                        fpos += mpc_bits_read(&d->bits_reader, 20) + 20;
+                        mpc_demux_seek(d, fpos, 4);
+                        d->d->decoded_samples += MPC_FRAME_LENGTH;
+                }
+        }
+        d->d->samples_to_skip = samples_to_skip;
+        return MPC_STATUS_OK;
+}