--- /dev/null
+/*****************************************************************************
+ * smf.c : Standard MIDI File (.mid) demux module for vlc
+ *****************************************************************************
+ * Copyright © 2007 Rémi Denis-Courmont
+ * $Id$
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#include <vlc/vlc.h>
+#include <vlc_demux.h>
+#include <vlc_aout.h>
+#include <vlc_codecs.h>
+#include <limits.h>
+
+static int Open (vlc_object_t *);
+static void Close (vlc_object_t *);
+
+vlc_module_begin ();
+ set_description (_("SMF demuxer"));
+ set_category (CAT_INPUT);
+ set_subcategory (SUBCAT_INPUT_DEMUX);
+ set_capability ("demux2", 20);
+ set_callbacks (Open, Close);
+vlc_module_end ();
+
+static int Demux (demux_t *);
+static int Control (demux_t *, int i_query, va_list args);
+
+typedef struct smf_track_t
+{
+ int64_t offset; /* Read offset in the file (stream_Tell) */
+ int64_t end; /* End offset in the file */
+ uint64_t next; /* Time of next message (in term of pulses) */
+ uint8_t running_event; /* Running (previous) event */
+} mtrk_t;
+
+static int ReadDeltaTime (stream_t *s, mtrk_t *track);
+
+struct demux_sys_t
+{
+ es_format_t fmt;
+ es_out_id_t *es;
+ date_t pts;
+ uint64_t pulse; /* Pulses counter */
+
+ unsigned ppqn; /* Pulses Per Quarter Note */
+ /* by the way, "quarter note" is "noire" in French */
+
+ unsigned trackc; /* Number of tracks */
+ mtrk_t trackv[0]; /* Track states */
+};
+
+/*****************************************************************************
+ * Open: check file and initializes structures
+ *****************************************************************************/
+static int Open (vlc_object_t * p_this)
+{
+ demux_t *p_demux = (demux_t *)p_this;
+ stream_t *stream = p_demux->s;
+ demux_sys_t *p_sys;
+ const uint8_t *peek;
+ unsigned tracks, ppqn;
+ vlc_bool_t multitrack;
+
+ /* (Try to) parse the SMF header */
+ /* Header chunk always has 6 bytes payload */
+ if (stream_Peek (stream, &peek, 14) < 14)
+ return VLC_EGENERIC;
+
+ if (memcmp (peek, "MThd\x00\x00\x00\x06", 8))
+ return VLC_EGENERIC;
+ peek += 8;
+
+ /* First word: SMF type */
+ switch (GetWBE (peek))
+ {
+ case 0:
+ multitrack = VLC_FALSE;
+ break;
+ case 1:
+ multitrack = VLC_TRUE;
+ break;
+ default:
+ /* We don't implement SMF2 (as do many) */
+ msg_Err (p_this, "unsupported SMF file type %u", GetWBE (peek));
+ return VLC_EGENERIC;
+ }
+ peek += 2;
+
+ /* Second word: number of tracks */
+ tracks = GetWBE (peek);
+ peek += 2;
+ if (!multitrack && (tracks != 1))
+ {
+ msg_Err (p_this, "invalid SMF type 0 file");
+ return VLC_EGENERIC;
+ }
+
+ msg_Dbg (p_this, "detected Standard MIDI File (type %u) with %u track(s)",
+ multitrack, tracks);
+
+ /* Third/last word: timing */
+ ppqn = GetWBE (peek);
+ if (ppqn & 0x8000)
+ {
+ /* FIXME */
+ msg_Err (p_this, "SMPTE timestamps not implemented");
+ return VLC_EGENERIC;
+ }
+ else
+ {
+ msg_Dbg (p_this, " %u pulses per quarter note", ppqn);
+ }
+
+ p_sys = malloc (sizeof (*p_sys) + (sizeof (mtrk_t) * tracks));
+ if (p_sys == NULL)
+ return VLC_ENOMEM;
+
+ /* We've had a valid SMF header - now skip it*/
+ if (stream_Read (stream, NULL, 14) < 14)
+ goto error;
+
+ p_demux->pf_demux = Demux;
+ p_demux->pf_control = Control;
+ p_demux->p_sys = p_sys;
+
+ es_format_Init (&p_sys->fmt, AUDIO_ES, VLC_FOURCC('M', 'I', 'D', 'I'));
+ p_sys->es = NULL;
+ /* SMF expresses tempo in Beats-Per-Minute, default is 120 */
+ date_Init (&p_sys->pts, ppqn * 120, 60);
+ p_sys->pulse = 0;
+ p_sys->ppqn = ppqn;
+
+ p_sys->trackc = tracks;
+ /* Prefetch track offsets */
+ for (unsigned i = 0; i < tracks; i++)
+ {
+ uint8_t head[8];
+
+ if (i > 0)
+ {
+ /* Seeking screws streaming up, but there is no way around this,
+ * as SMF1 tracks are performed simultaneously.
+ * Not a big deal as SMF1 are usually only a few kbytes anyway. */
+ if (stream_Seek (stream, p_sys->trackv[i-1].end))
+ {
+ msg_Err (p_this, "cannot build SMF index (corrupted file?)");
+ goto error;
+ }
+ }
+
+ for (;;)
+ {
+ stream_Read (stream, head, 8);
+ if (memcmp (head, "MTrk", 4) == 0)
+ break;
+
+ msg_Dbg (p_this, "skipping unknown SMF chunk");
+ stream_Read (stream, NULL, GetDWBE (head + 4));
+ }
+
+ p_sys->trackv[i].offset = stream_Tell (stream);
+ p_sys->trackv[i].end = p_sys->trackv[i].offset + GetDWBE (head + 4);
+ msg_Dbg (p_this, "track %u: 0x"I64Fx"-0x"I64Fx, i,
+ p_sys->trackv[i].offset, p_sys->trackv[i].end);
+ p_sys->trackv[i].next = 0;
+ ReadDeltaTime (stream, p_sys->trackv + i);
+ p_sys->trackv[i].running_event = 0xF6;
+ /* Why 0xF6 (Tuning Calibration)?
+ * Because it has zero bytes of data, so the parser will detect the
+ * error if the first event uses running status. */
+ }
+
+ return VLC_SUCCESS;
+
+error:
+ free (p_sys);
+ return VLC_EGENERIC;
+}
+
+/**
+ * Releases allocate resources.
+ */
+static void Close (vlc_object_t * p_this)
+{
+ demux_t *p_demux = (demux_t *)p_this;
+ demux_sys_t *p_sys = p_demux->p_sys;
+
+ free (p_sys);
+}
+
+/**
+ * Reads MIDI variable length (7, 14, 21 or 28 bits) integer.
+ * @return read value, or -1 on EOF/error.
+ */
+static int32_t ReadVarInt (stream_t *s)
+{
+ uint32_t val = 0;
+ uint8_t byte;
+
+ for (unsigned i = 0; i < 4; i++)
+ {
+ if (stream_Read (s, &byte, 1) < 1)
+ return -1;
+
+ val = (val << 7) | (byte & 0x7f);
+ if ((byte & 0x80) == 0)
+ return val;
+ }
+
+ return -1;
+}
+
+
+/**
+ * Reads (delta) time from the next event of a given track.
+ * @param s stream to read data from (must be positioned at the right offset)
+ */
+static int ReadDeltaTime (stream_t *s, mtrk_t *track)
+{
+ int32_t delta_time;
+
+ assert (stream_Tell (s) == track->offset);
+
+ if (track->offset >= track->end)
+ {
+ /* This track is done */
+ track->next = UINT64_MAX;
+ return 0;
+ }
+
+ delta_time = ReadVarInt (s);
+ if (delta_time < 0)
+ return -1;
+
+ track->next += delta_time;
+ track->offset = stream_Tell (s);
+ return 0;
+}
+
+
+static
+int HandleMessage (demux_t *p_demux, mtrk_t *tr)
+{
+ stream_t *s = p_demux->s;
+ block_t *block;
+ uint8_t first, event;
+ unsigned datalen;
+
+ if (stream_Seek (s, tr->offset)
+ || (stream_Read (s, &first, 1) != 1))
+ return -1;
+
+ event = (first & 0x80) ? first : tr->running_event;
+ msg_Dbg (p_demux, "MIDI event 0x%02X", event);
+
+ switch (event & 0xf0)
+ {
+ case 0xF0: /* System Exclusive */
+ switch (event)
+ {
+ case 0xF0: /* System Specific */
+ {
+ /* TODO: don't skip these */
+ stream_Read (s, NULL, 1); /* Manuf ID */
+ for (;;)
+ {
+ uint8_t c;
+ if (stream_Read (s, &c, 1) != 1)
+ return -1;
+ if (c == 0xF7)
+ goto skip;
+ }
+ }
+ case 0xFF: /* SMF Meta Event */
+ {
+ uint8_t type;
+ int32_t length;
+
+ if (stream_Read (s, &type, 1) != 1)
+ return -1;
+ length = ReadVarInt (s);
+ if (length < 0)
+ return -1;
+
+ msg_Warn (p_demux,
+ "unknown SMF Meta Event type 0x%02X (%d bytes)",
+ type, length);
+ /* TODO: parse these */
+ if (stream_Read (s, NULL, length) != length)
+ return -1;
+
+ /* We MUST NOT pass this event to forward. It would be
+ * confused as a MIDI Reset real-time event. */
+ goto skip;
+ }
+ case 0xF1:
+ case 0xF3:
+ datalen = 1;
+ break;
+ case 0xF2:
+ datalen = 2;
+ break;
+ case 0xF4:
+ case 0xF5:
+ /* We cannot handle undefined "common" (non-real-time)
+ * events inside SMF, as we cannot differentiate a
+ * one byte delta-time (< 0x80) from event data. */
+ case 0xF7: /* End of sysex -> should never happen(?) */
+ msg_Err (p_demux, "unknown MIDI event 0x%02X", event);
+ return -1; /* undefined events */
+ default:
+ datalen = 0;
+ break;
+ }
+ case 0xC0:
+ case 0xD0:
+ datalen = 1;
+ break;
+ default:
+ datalen = 2;
+ break;
+ }
+
+ /* FIXME: one message per block is very inefficient */
+ block = block_New (p_demux, 1 + datalen);
+ if (block == NULL)
+ goto skip;
+
+ block->p_buffer[0] = event;
+ if (first & 0x80)
+ {
+ stream_Read (s, block->p_buffer + 1, datalen);
+ }
+ else
+ {
+ if (datalen == 0)
+ {
+ msg_Err (p_demux, "malformatted MIDI event");
+ return -1; /* can't use implicit running status with empty payload! */
+ }
+
+ block->p_buffer[1] = first;
+ if (datalen > 1)
+ stream_Read (s, block->p_buffer + 2, datalen - 1);
+ }
+
+#if 0
+ es_out_Send (p_demux->out, p_demux->p_sys->es, block);
+#else
+ block_Release (block);
+#endif
+
+skip:
+ if (event < 0xF8)
+ /* If event is not real-time, update running status */
+ tr->running_event = event;
+
+ tr->offset = stream_Tell (s);
+ return 0;
+}
+
+/*****************************************************************************
+ * Demux: read chunks and send them to the synthetizer
+ *****************************************************************************
+ * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
+ *****************************************************************************/
+static int Demux (demux_t *p_demux)
+{
+ stream_t *s = p_demux->s;
+ demux_sys_t *p_sys = p_demux->p_sys;
+ uint64_t pulse = p_sys->pulse, next_pulse = UINT64_MAX;
+
+ if (pulse == UINT64_MAX)
+ return 0; /* all tracks are done */
+
+ /*p_block->i_dts = p_block->i_pts =
+ date_Increment( &p_sys->pts, p_sys->fmt.audio.i_frame_length );
+
+ es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );*/
+
+
+ msg_Dbg (p_demux, "pulse %llu", pulse);
+ for (unsigned i = 0; i < p_sys->trackc; i++)
+ {
+ mtrk_t *track = p_sys->trackv + i;
+
+ while (track->next == pulse)
+ {
+ msg_Dbg (p_demux, "event on track %u", i);
+ if (HandleMessage (p_demux, track)
+ || ReadDeltaTime (s, track))
+ {
+ msg_Err (p_demux, "fatal parsing error");
+ return VLC_EGENERIC;
+ }
+ }
+
+ if (track->next < next_pulse)
+ next_pulse = track->next;
+ }
+ p_sys->pulse = next_pulse;
+
+ return 1;
+}
+
+
+/*****************************************************************************
+ * Control:
+ *****************************************************************************/
+static int Control (demux_t *p_demux, int i_query, va_list args)
+{
+ demux_sys_t *p_sys = p_demux->p_sys;
+
+ return demux2_vaControlHelper (p_demux->s, 0, -1,
+ p_sys->fmt.i_bitrate,
+ p_sys->fmt.audio.i_blockalign,
+ i_query, args);
+}
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