Preliminary incomplete Standard MIDI File demux

(Still missing the ES out so pretty useless, but got to sleep now)

modules/demux/Modules.am

@@ -29,3 +29,4 @@ SOURCES_gme = gme.cpp
 SOURCES_tta = tta.c
 SOURCES_vc1 = vc1.c
 SOURCES_demux_cdg = cdg.c
+SOURCES_smf = smf.c

modules/demux/smf.c

+/*****************************************************************************
+ * 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);
+}