gstreamer/gst/asfdemux/asfpacket.c

/* GStreamer ASF/WMV/WMA demuxer
 * Copyright (C) 2007 Tim-Philipp Müller <tim centricular net>
 *
 * 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.
 */

/* FIXME:
 *  file:///home/tpm/samples/video/asf//336370-regis-velo862.wmv
 *  file:///home/tpm/samples/video/asf//336370-eichhoer.wmv
 * throw errors (not always necessarily) in this code path
 * (looks like they carry broken payloads/packets though) */

#include "asfpacket.h"

#include <gst/gstutils.h>
#include <gst/gstinfo.h>
#include <string.h>

/* we are unlikely to deal with lengths > 2GB here any time soon, so just
 * return a signed int and use that for error reporting */
static gint
asf_packet_read_varlen_int (guint lentype_flags, guint lentype_bit_offset,
    const guint8 ** p_data, guint * p_size)
{
  const guint lens[4] = { 0, 1, 2, 4 };
  guint len, val;

  len = lens[(lentype_flags >> lentype_bit_offset) & 0x03];

  /* will make caller bail out with a short read if there's not enough data */
  if (*p_size < len) {
    GST_WARNING ("need %u bytes, but only %u bytes available", len, *p_size);
    return -1;
  }

  switch (len) {
    case 0:
      val = 0;
      break;
    case 1:
      val = GST_READ_UINT8 (*p_data);
      break;
    case 2:
      val = GST_READ_UINT16_LE (*p_data);
      break;
    case 4:
      val = GST_READ_UINT32_LE (*p_data);
      break;
    default:
      g_assert_not_reached ();
  }

  *p_data += len;
  *p_size -= len;

  return (gint) val;
}

static GstBuffer *
asf_packet_create_payload_buffer (AsfPacket * packet, const guint8 ** p_data,
    guint * p_size, guint payload_len)
{
  guint off;

  g_assert (payload_len <= *p_size);

  off = (guint) (*p_data - GST_BUFFER_DATA (packet->buf));
  g_assert (off < GST_BUFFER_SIZE (packet->buf));

  *p_data += payload_len;
  *p_size -= payload_len;

  return gst_buffer_create_sub (packet->buf, off, payload_len);
}

static AsfPayload *
asf_payload_find_previous_fragment (AsfPayload * payload, AsfStream * stream)
{
  AsfPayload *ret;

  if (stream->payloads->len == 0) {
    GST_DEBUG ("No previous fragments to merge with for stream %u", stream->id);
    return NULL;
  }

  ret =
      &g_array_index (stream->payloads, AsfPayload, stream->payloads->len - 1);

  if (ret->mo_size != payload->mo_size ||
      ret->mo_number != payload->mo_number || ret->mo_offset != 0) {
    GST_WARNING ("Previous fragment does not match continued fragment");
    return NULL;
  }
#if 0
  if (this_fragment->mo_offset + this_payload_len > first_fragment->mo_size) {
    GST_WARNING ("Merged fragments would be bigger than the media object");
    return FALSE;
  }
#endif

  return ret;
}

static void
gst_asf_payload_queue_for_stream (GstASFDemux * demux, AsfPayload * payload,
    AsfStream * stream)
{
  /* remove any incomplete payloads that will never be completed */
  while (stream->payloads->len > 0) {
    AsfPayload *prev;
    guint idx_last;

    idx_last = stream->payloads->len - 1;
    prev = &g_array_index (stream->payloads, AsfPayload, idx_last);

    if (gst_asf_payload_is_complete (prev))
      break;

    GST_DEBUG_OBJECT (demux, "Dropping incomplete fragmented media object "
        "queued for stream %u", stream->id);

    gst_buffer_replace (&prev->buf, NULL);
    g_array_remove_index (stream->payloads, idx_last);

    /* there's data missing, so there's a discontinuity now */
    GST_BUFFER_FLAG_SET (payload->buf, GST_BUFFER_FLAG_DISCONT);
  }

  g_array_append_vals (stream->payloads, payload, 1);
}

static gboolean
gst_asf_demux_parse_payload (GstASFDemux * demux, AsfPacket * packet,
    gint lentype, const guint8 ** p_data, guint * p_size)
{
  AsfPayload payload = { 0, };
  AsfStream *stream;
  gboolean is_compressed;
  guint payload_len;
  guint stream_num;

  if (*p_size < 1) {
    GST_WARNING_OBJECT (demux, "Short packet!");
    return FALSE;
  }

  stream_num = GST_READ_UINT8 (*p_data) & 0x7f;
  payload.keyframe = ((GST_READ_UINT8 (*p_data) & 0x80) != 0);

  *p_data += 1;
  *p_size -= 1;

  payload.mo_number =
      asf_packet_read_varlen_int (packet->prop_flags, 4, p_data, p_size);
  payload.mo_offset =
      asf_packet_read_varlen_int (packet->prop_flags, 2, p_data, p_size);
  payload.rep_data_len =
      asf_packet_read_varlen_int (packet->prop_flags, 0, p_data, p_size);

  is_compressed = (payload.rep_data_len == 1);

  GST_LOG_OBJECT (demux, "payload for stream %u", stream_num);
  GST_LOG_OBJECT (demux, "keyframe   : %s", (payload.keyframe) ? "yes" : "no");
  GST_LOG_OBJECT (demux, "compressed : %s", (is_compressed) ? "yes" : "no");

  if (*p_size < payload.rep_data_len) {
    GST_WARNING_OBJECT (demux, "Short packet! rep_data_len=%u, size=%u",
        payload.rep_data_len, *p_size);
    return FALSE;
  }

  memcpy (payload.rep_data, *p_data,
      MIN (sizeof (payload.rep_data), payload.rep_data_len));

  *p_data += payload.rep_data_len;
  *p_size -= payload.rep_data_len;

  if (*p_size == 0) {
    GST_WARNING_OBJECT (demux, "payload without data!?");
    return FALSE;
  }

  /* we use -1 as lentype for a single payload that's the size of the packet */
  if (lentype >= 0 && lentype <= 3) {
    payload_len = asf_packet_read_varlen_int (lentype, 0, p_data, p_size);
    if (*p_size < payload_len) {
      GST_WARNING_OBJECT (demux, "Short packet! payload_len=%u, size=%u",
          payload_len, *p_size);
      return FALSE;
    }
  } else {
    payload_len = *p_size;
  }

  GST_LOG_OBJECT (demux, "payload length: %u", payload_len);

  stream = gst_asf_demux_get_stream (demux, stream_num);

  if (stream == NULL) {
    GST_WARNING_OBJECT (demux, "Payload for unknown stream %u, skipping",
        stream_num);
    *p_data += payload_len;
    *p_size -= payload_len;
    return TRUE;
  }

  if (!is_compressed) {
    GstClockTime ts = GST_CLOCK_TIME_NONE;

    GST_LOG_OBJECT (demux, "replicated data length: %u", payload.rep_data_len);

    if (payload.rep_data_len >= 8) {
      payload.mo_size = GST_READ_UINT32_LE (payload.rep_data);
      ts = GST_READ_UINT32_LE (payload.rep_data + 4) * GST_MSECOND;
      ts -= demux->preroll * GST_MSECOND;

      GST_LOG_OBJECT (demux, "media object size   : %u", payload.mo_size);
      GST_LOG_OBJECT (demux, "media object ts     : %" GST_TIME_FORMAT,
          GST_TIME_ARGS (ts));
      /* TODO: parse payload extensions, if there are any */
    } else if (payload.rep_data_len != 0) {
      GST_WARNING_OBJECT (demux, "invalid replicated data length, very bad");
    }

    GST_LOG_OBJECT (demux, "media object offset : %u", payload.mo_offset);

    GST_LOG_OBJECT (demux, "payload length: %u", payload_len);

    if ((stream = gst_asf_demux_get_stream (demux, stream_num))) {
      payload.buf = asf_packet_create_payload_buffer (packet, p_data, p_size,
          payload_len);

      /* n-th fragment of a fragmented media object? */
      if (payload.mo_offset != 0) {
        AsfPayload *prev;

        if ((prev = asf_payload_find_previous_fragment (&payload, stream))) {
          if (payload.mo_offset != GST_BUFFER_SIZE (prev->buf)) {
            GST_WARNING_OBJECT (demux, "Offset doesn't match previous data?!");
          }
          /* note: buffer join/merge might not preserve buffer flags */
          prev->buf = gst_buffer_join (prev->buf, payload.buf);
          GST_LOG_OBJECT (demux, "Merged fragments, merged size: %u",
              GST_BUFFER_SIZE (prev->buf));
        } else {
          gst_buffer_unref (payload.buf);
        }
        payload.buf = NULL;
      } else {
        GST_BUFFER_TIMESTAMP (payload.buf) = ts;
        gst_asf_payload_queue_for_stream (demux, &payload, stream);
      }
    }
  } else {
    const guint8 *payload_data;
    GstClockTime ts, ts_delta;
    guint num;

    GST_LOG_OBJECT (demux, "Compressed payload, length=%u", payload_len);

    payload_data = *p_data;

    *p_data += payload_len;
    *p_size -= payload_len;

    ts = (payload.mo_offset - demux->preroll) * GST_MSECOND;
    ts_delta = payload.rep_data[0] * GST_MSECOND;

    for (num = 0; payload_len > 0; ++num) {
      guint sub_payload_len;

      sub_payload_len = GST_READ_UINT8 (payload_data);

      GST_LOG_OBJECT (demux, "subpayload #%u: len=%u, ts=%" GST_TIME_FORMAT,
          num, sub_payload_len, GST_TIME_ARGS (ts));

      ++payload_data;
      --payload_len;

      if (payload_len < sub_payload_len) {
        GST_WARNING_OBJECT (demux, "Short payload! %u bytes left", payload_len);
        return FALSE;
      }

      payload.buf = asf_packet_create_payload_buffer (packet,
          &payload_data, &payload_len, sub_payload_len);

      GST_BUFFER_TIMESTAMP (payload.buf) = ts;
      GST_BUFFER_DURATION (payload.buf) = ts_delta;
      gst_asf_payload_queue_for_stream (demux, &payload, stream);

      ts += ts_delta;
    }
  }

  return TRUE;
}

gboolean
gst_asf_demux_parse_packet (GstASFDemux * demux, GstBuffer * buf)
{
  AsfPacket packet = { 0, };
  const guint8 *data;
  gboolean has_multiple_payloads;
  gboolean ret = TRUE;
  guint8 ec_flags, flags1;
  guint size;

  data = GST_BUFFER_DATA (buf);
  size = GST_BUFFER_SIZE (buf);

  /* need at least two payload flag bytes, send time, and duration */
  if (size < 2 + 4 + 2)
    goto short_packet;

  packet.buf = buf;

  ec_flags = GST_READ_UINT8 (data);

  /* skip optional error correction stuff */
  if ((ec_flags & 0x80) != 0) {
    guint ec_len_type, ec_len;

    ec_len_type = (ec_flags & 0x60) >> 5;
    if (ec_len_type == 0) {
      ec_len = ec_flags & 0x0f;
    } else {
      GST_WARNING_OBJECT (demux, "unexpected error correction length type %u",
          ec_len_type);
      ec_len = 2;
    }
    GST_LOG ("packet has error correction (%u bytes)", ec_len);

    /* still need at least two payload flag bytes, send time, and duration */
    if (size <= (1 + ec_len) + 2 + 4 + 2)
      goto short_packet;

    data += 1 + ec_len;
    size -= 1 + ec_len;
  }

  /* parse payload info */
  flags1 = GST_READ_UINT8 (data);
  packet.prop_flags = GST_READ_UINT8 (data + 1);

  data += 2;
  size -= 2;

  has_multiple_payloads = (flags1 & 0x01) != 0;

  packet.length = asf_packet_read_varlen_int (flags1, 5, &data, &size);

  packet.sequence = asf_packet_read_varlen_int (flags1, 1, &data, &size);

  packet.padding = asf_packet_read_varlen_int (flags1, 3, &data, &size);

  if (size < 6)
    goto short_packet;

  packet.send_time = GST_READ_UINT32_LE (data) * GST_MSECOND;
  packet.duration = GST_READ_UINT16_LE (data + 4) * GST_MSECOND;

  data += 4 + 2;
  size -= 4 + 2;

  GST_LOG_OBJECT (demux, "multiple payloads: %u", has_multiple_payloads);
  GST_LOG_OBJECT (demux, "packet length    : %u", packet.length);
  GST_LOG_OBJECT (demux, "sequence         : %u", packet.sequence);
  GST_LOG_OBJECT (demux, "padding          : %u", packet.padding);
  GST_LOG_OBJECT (demux, "send time        : %" GST_TIME_FORMAT,
      GST_TIME_ARGS (packet.send_time));
  GST_LOG_OBJECT (demux, "duration         : %" GST_TIME_FORMAT,
      GST_TIME_ARGS (packet.duration));

  if (packet.padding == (guint) - 1 || size < packet.padding)
    goto short_packet;

  size -= packet.padding;

  if (has_multiple_payloads) {
    guint i, num, lentype;

    if (size < 1)
      goto short_packet;

    num = (GST_READ_UINT8 (data) & 0x3F) >> 0;
    lentype = (GST_READ_UINT8 (data) & 0xC0) >> 6;

    ++data;
    --size;

    GST_LOG_OBJECT (demux, "num payloads     : %u", num);

    for (i = 0; i < num; ++i) {
      GST_LOG_OBJECT (demux, "Parsing payload %u/%u", i + 1, num);

      ret = gst_asf_demux_parse_payload (demux, &packet, lentype, &data, &size);

      if (!ret) {
        GST_WARNING_OBJECT (demux, "Failed to parse payload %u/%u", i + 1, num);
        break;
      }
    }
  } else {
    GST_LOG_OBJECT (demux, "Parsing single payload");
    ret = gst_asf_demux_parse_payload (demux, &packet, -1, &data, &size);
  }

  return ret;

/* ERRORS */
short_packet:
  {
    GST_WARNING_OBJECT (demux, "Short packet!");
    return FALSE;
  }
}