/*

 * Copyright (c) 2006 Christophe Fergeau  <teuf@gnome.org>

 * Copyright (c) 2008 Sebastian Dröge  <slomo@circular-chaos.org>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

/* Xing SDK: http://www.mp3-tech.org/programmer/sources/vbrheadersdk.zip */

/**

 * SECTION:element-xingmux

 *

 * xingmux adds a Xing header to MP3 files. This contains information about the duration and size

 * of the file and a seek table and is very useful for getting an almost correct duration and better

 * seeking on VBR MP3 files.

 * 

 * This element will remove any existing Xing, LAME or VBRI headers from the beginning of the file.

 *

 * <refsect2>

 * <title>Example launch line</title>

 * |[

 * gst-launch audiotestsrc num-buffers=1000 ! audioconvert ! lame ! xingmux ! filesink location=test.mp3

 * gst-launch filesrc location=test.mp3 ! xingmux ! filesink location=test2.mp3

 * gst-launch filesrc location=test.mp3 ! mp3parse ! xingmux ! filesink location=test2.mp3

 * ]|

 * </refsect2>

 */

#ifdef HAVE_CONFIG_H

#include "../../config.h"

#endif

#include <string.h>

#include "gstxingmux.h"

GST_DEBUG_CATEGORY_STATIC (xing_mux_debug);

#define GST_CAT_DEFAULT xing_mux_debug

GST_BOILERPLATE (GstXingMux, gst_xing_mux, GstElement, GST_TYPE_ELEMENT);

/* Xing Header stuff */

#define GST_XING_FRAME_FIELD   (1 << 0)

#define GST_XING_BYTES_FIELD   (1 << 1)

#define GST_XING_TOC_FIELD     (1 << 2)

#define GST_XING_QUALITY_FIELD (1 << 3)

typedef struct _GstXingSeekEntry

{

  gint64 timestamp;

  gint byte;

} GstXingSeekEntry;

static inline GstXingSeekEntry *

gst_xing_seek_entry_new ()

{

  return g_slice_new (GstXingSeekEntry);

}

static inline void

gst_xing_seek_entry_free (GstXingSeekEntry * entry)

{

  g_slice_free (GstXingSeekEntry, entry);

}

static void gst_xing_mux_finalize (GObject * obj);

static GstStateChangeReturn

gst_xing_mux_change_state (GstElement * element, GstStateChange transition);

static GstFlowReturn gst_xing_mux_chain (GstPad * pad, GstBuffer * buffer);

static gboolean gst_xing_mux_sink_event (GstPad * pad, GstEvent * event);

static GstStaticPadTemplate gst_xing_mux_sink_template =

GST_STATIC_PAD_TEMPLATE ("sink",

    GST_PAD_SINK,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS ("audio/mpeg, "

        "mpegversion = (int) 1, " "layer = (int) [ 1, 3 ]"));

static GstStaticPadTemplate gst_xing_mux_src_template =

GST_STATIC_PAD_TEMPLATE ("src",

    GST_PAD_SRC,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS ("audio/mpeg, "

        "mpegversion = (int) 1, " "layer = (int) [ 1, 3 ]"));

static const guint mp3types_bitrates[2][3][16] = {

  {

        {0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448,},

        {0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,},

        {0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,}

      },

  {

        {0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256,},

        {0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,},

        {0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,}

      },

};

static const guint mp3types_freqs[3][3] = { {44100, 48000, 32000},

{22050, 24000, 16000},

{11025, 12000, 8000}

};

static gboolean

parse_header (guint32 header, guint * ret_size, guint * ret_spf,

    gulong * ret_rate)

{

  guint length, spf;

  gulong samplerate, bitrate, layer, padding;

  gint lsf, mpg25;

  if ((header & 0xffe00000) != 0xffe00000) {

    g_warning ("invalid sync");

    return FALSE;

  }

  if (((header >> 19) & 3) == 0x01) {

    g_warning ("invalid MPEG version");

    return FALSE;

  }

  if (((header >> 17) & 3) == 0x00) {

    g_warning ("invalid MPEG layer");

    return FALSE;

  }

  if (((header >> 12) & 0xf) == 0xf || ((header >> 12) & 0xf) == 0x0) {

    g_warning ("invalid bitrate");

    return FALSE;

  }

  if (((header >> 10) & 0x3) == 0x3) {

    g_warning ("invalid sampling rate");

    return FALSE;

  }

  if (header & 0x00000002) {

    g_warning ("invalid emphasis");

    return FALSE;

  }

  if (header & (1 << 20)) {

    lsf = (header & (1 << 19)) ? 0 : 1;

    mpg25 = 0;

  } else {

    lsf = 1;

    mpg25 = 1;

  }

  layer = 4 - ((header >> 17) & 0x3);

  bitrate = (header >> 12) & 0xF;

  bitrate = mp3types_bitrates[lsf][layer - 1][bitrate] * 1000;

  if (bitrate == 0)

    return 0;

  samplerate = (header >> 10) & 0x3;

  samplerate = mp3types_freqs[lsf + mpg25][samplerate];

  padding = (header >> 9) & 0x1;

  switch (layer) {

    case 1:

      length = 4 * ((bitrate * 12) / samplerate + padding);

      break;

    case 2:

      length = (bitrate * 144) / samplerate + padding;

      break;

    default:

    case 3:

      length = (bitrate * 144) / (samplerate << lsf) + padding;

      break;

  }

  if (layer == 1)

    spf = 384;

  else if (layer == 2 || lsf == 0)

    spf = 1152;

  else

    spf = 576;

  if (ret_size)

    *ret_size = length;

  if (ret_spf)

    *ret_spf = spf;

  if (ret_rate)

    *ret_rate = samplerate;

  return TRUE;

}

static guint

get_xing_offset (guint32 header)

{

  guint mpeg_version = (header >> 19) & 0x3;

  guint channel_mode = (header >> 6) & 0x3;

  if (mpeg_version == 0x3) {

    if (channel_mode == 0x3) {

      return 0x11;

    } else {

      return 0x20;

    }

  } else {

    if (channel_mode == 0x3) {

      return 0x09;

    } else {

      return 0x11;

    }

  }

}

static gboolean

has_xing_header (guint32 header, guchar * data, gsize size)

{

  data += 4;

  data += get_xing_offset (header);

  if (memcmp (data, "Xing", 4) == 0 ||

      memcmp (data, "Info", 4) == 0 || memcmp (data, "VBRI", 4) == 0)

    return TRUE;

  else

    return FALSE;

}

static GstBuffer *

generate_xing_header (GstXingMux * xing)

{

  guint8 *xing_flags;

  guint32 xing_flags_tmp = 0;

  GstBuffer *xing_header;

  guchar *data;

  guint32 header;

  guint32 header_be;

  guint size, spf, xing_offset;

  gulong rate;

  guint bitrate = 0x00;

  gint64 duration;

  gint64 byte_count;

  header = xing->first_header;

  /* Set bitrate and choose lowest possible size */

  do {

    bitrate++;

    header &= 0xffff0fff;

    header |= bitrate << 12;

    parse_header (header, &size, &spf, &rate);

    xing_offset = get_xing_offset (header);

  } while (size < (4 + xing_offset + 4 + 4 + 4 + 4 + 100) && bitrate < 0xe);

  if (bitrate == 0xe) {

    GST_ERROR ("No usable bitrate found!");

    return NULL;

  }

  if (gst_pad_alloc_buffer_and_set_caps (xing->srcpad, 0, size,

          GST_PAD_CAPS (xing->srcpad), &xing_header) != GST_FLOW_OK) {

    xing_header = gst_buffer_new_and_alloc (size);

    gst_buffer_set_caps (xing_header, GST_PAD_CAPS (xing->srcpad));

  }

  data = GST_BUFFER_DATA (xing_header);

  memset (data, 0, size);

  header_be = GUINT32_TO_BE (header);

  memcpy (data, &header_be, 4);

  data += 4;

  data += xing_offset;

  memcpy (data, "Xing", 4);

  data += 4;

  xing_flags = data;

  data += 4;

  if (xing->duration != GST_CLOCK_TIME_NONE) {

    duration = xing->duration;

  } else {

    GstFormat fmt = GST_FORMAT_TIME;

    if (!gst_pad_query_peer_duration (xing->sinkpad, &fmt, &duration))

      duration = GST_CLOCK_TIME_NONE;

  }

  if (duration != GST_CLOCK_TIME_NONE) {

    guint32 number_of_frames;

    /* The Xing Header contains a NumberOfFrames field, which verifies to:

     * Duration = NumberOfFrames *SamplesPerFrame/SamplingRate

     * SamplesPerFrame and SamplingRate are values for the current frame. 

     */

    number_of_frames = gst_util_uint64_scale (duration, rate, GST_SECOND) / spf;

    GST_DEBUG ("Setting number of frames to %u", number_of_frames);

    number_of_frames = GUINT32_TO_BE (number_of_frames);

    memcpy (data, &number_of_frames, 4);

    xing_flags_tmp |= GST_XING_FRAME_FIELD;

    data += 4;

  }

  if (xing->byte_count != 0) {

    byte_count = xing->byte_count;

  } else {

    GstFormat fmt = GST_FORMAT_BYTES;

    if (!gst_pad_query_peer_duration (xing->sinkpad, &fmt, &byte_count))

      byte_count = 0;

    if (byte_count == -1)

      byte_count = 0;

  }

  if (byte_count != 0) {

    guint32 nbytes;

    if (byte_count > G_MAXUINT32) {

      GST_DEBUG ("Too large stream: %" G_GINT64_FORMAT " > %u bytes",

          byte_count, G_MAXUINT32);

    } else {

      nbytes = byte_count;

      GST_DEBUG ("Setting number of bytes to %u", nbytes);

      nbytes = GUINT32_TO_BE (nbytes);

      memcpy (data, &nbytes, 4);

      xing_flags_tmp |= GST_XING_BYTES_FIELD;

      data += 4;

    }

  }

  if (xing->seek_table != NULL && byte_count != 0

      && duration != GST_CLOCK_TIME_NONE) {

    GList *it;

    gint percent = 0;

    xing_flags_tmp |= GST_XING_TOC_FIELD;

    GST_DEBUG ("Writing seek table");

    for (it = xing->seek_table; it != NULL && percent < 100; it = it->next) {

      GstXingSeekEntry *entry = (GstXingSeekEntry *) it->data;

      gint64 pos;

      guchar byte;

      while ((entry->timestamp * 100) / duration >= percent) {

        pos = (entry->byte * 256) / byte_count;

        GST_DEBUG ("  %d %% -- %" G_GINT64_FORMAT " 1/256", percent, pos);

        byte = (guchar) pos;

        memcpy (data, &byte, 1);

        data++;

        percent++;

      }

    }

    if (percent < 100) {

      guchar b;

      gint i;

      memcpy (&b, data - 1, 1);

      for (i = percent; i < 100; i++) {

        GST_DEBUG ("  %d %% -- %d 1/256", i, b);

        memcpy (data, &b, 1);

        data++;

      }

    }

  }

  GST_DEBUG ("Setting Xing flags to 0x%x\n", xing_flags_tmp);

  xing_flags_tmp = GUINT32_TO_BE (xing_flags_tmp);

  memcpy (xing_flags, &xing_flags_tmp, 4);

  return xing_header;

}

static void

gst_xing_mux_base_init (gpointer g_class)

{

  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  static const GstElementDetails gst_xing_mux_details =

      GST_ELEMENT_DETAILS ("MP3 Xing muxer",

      "Formatter/Metadata",

      "Adds a Xing header to the beginning of a VBR MP3 file",

      "Christophe Fergeau <teuf@gnome.org>");

  gst_element_class_add_pad_template (element_class,

      gst_static_pad_template_get (&gst_xing_mux_src_template));

  gst_element_class_add_pad_template (element_class,

      gst_static_pad_template_get (&gst_xing_mux_sink_template));

  GST_DEBUG_CATEGORY_INIT (xing_mux_debug, "xingmux", 0, "Xing Header Muxer");

  gst_element_class_set_details (element_class, &gst_xing_mux_details);

}

static void

gst_xing_mux_class_init (GstXingMuxClass * klass)

{

  GObjectClass *gobject_class;

  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;

  gstelement_class = (GstElementClass *) klass;

  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_xing_mux_finalize);

  gstelement_class->change_state =

      GST_DEBUG_FUNCPTR (gst_xing_mux_change_state);

}

static void

gst_xing_mux_finalize (GObject * obj)

{

  GstXingMux *xing = GST_XING_MUX (obj);

  if (xing->adapter) {

    g_object_unref (xing->adapter);

    xing->adapter = NULL;

  }

  if (xing->seek_table) {

    g_list_foreach (xing->seek_table, (GFunc) gst_xing_seek_entry_free, NULL);

    g_list_free (xing->seek_table);

    xing->seek_table = NULL;

  }

  G_OBJECT_CLASS (parent_class)->finalize (obj);

}

static void

xing_reset (GstXingMux * xing)

{

  xing->duration = GST_CLOCK_TIME_NONE;

  xing->byte_count = 0;

  gst_adapter_clear (xing->adapter);

  if (xing->seek_table) {

    g_list_foreach (xing->seek_table, (GFunc) gst_xing_seek_entry_free, NULL);

    g_list_free (xing->seek_table);

    xing->seek_table = NULL;

  }

  xing->sent_xing = FALSE;

}

static void

gst_xing_mux_init (GstXingMux * xing, GstXingMuxClass * xingmux_class)

{

  GstElementClass *klass = GST_ELEMENT_CLASS (xingmux_class);

  /* pad through which data comes in to the element */

  xing->sinkpad =

      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,

          "sink"), "sink");

  gst_pad_set_setcaps_function (xing->sinkpad,

      GST_DEBUG_FUNCPTR (gst_pad_proxy_setcaps));

  gst_pad_set_chain_function (xing->sinkpad,

      GST_DEBUG_FUNCPTR (gst_xing_mux_chain));

  gst_pad_set_event_function (xing->sinkpad,

      GST_DEBUG_FUNCPTR (gst_xing_mux_sink_event));

  gst_element_add_pad (GST_ELEMENT (xing), xing->sinkpad);

  /* pad through which data goes out of the element */

  xing->srcpad =

      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,

          "src"), "src");

  gst_element_add_pad (GST_ELEMENT (xing), xing->srcpad);

  xing->adapter = gst_adapter_new ();

  xing_reset (xing);

}

static GstFlowReturn

gst_xing_mux_chain (GstPad * pad, GstBuffer * buffer)

{

  GstXingMux *xing = GST_XING_MUX (GST_PAD_PARENT (pad));

  GstFlowReturn ret = GST_FLOW_OK;

  gst_adapter_push (xing->adapter, buffer);

  while (gst_adapter_available (xing->adapter) >= 4) {

    const guchar *data = gst_adapter_peek (xing->adapter, 4);

    guint32 header;

    GstBuffer *outbuf;

    GstClockTime duration;

    guint size, spf;

    gulong rate;

    GstXingSeekEntry *seek_entry;

    header = GST_READ_UINT32_BE (data);

    if (!parse_header (header, &size, &spf, &rate)) {

      GST_DEBUG ("Lost sync, resyncing");

      gst_adapter_flush (xing->adapter, 1);

      continue;

    }

    if (gst_adapter_available (xing->adapter) < size)

      break;

    outbuf = gst_adapter_take_buffer (xing->adapter, size);

    gst_buffer_set_caps (outbuf, GST_PAD_CAPS (xing->srcpad));

    if (!xing->sent_xing) {

      if (has_xing_header (header, GST_BUFFER_DATA (outbuf), size)) {

        GST_LOG_OBJECT (xing, "Dropping old Xing header");

        gst_buffer_unref (outbuf);

        continue;

      } else {

        GstBuffer *xing_header;

        guint64 xing_header_size;

        xing->first_header = header;