modules/codec/gstdecode.c

   1 /*****************************************************************************
   2  * gstdecode.c: Decoder module making use of gstreamer
   3  *****************************************************************************
   4  * Copyright (C) 2014 VLC authors and VideoLAN
   5  * $Id:
   6  *
   7  * Author: Vikram Fugro <vikram.fugro@gmail.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Library General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Library General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_codec.h>
  34
  35 #include <gst/gst.h>
  36 #include <gst/video/video.h>
  37 #include <gst/video/gstvideometa.h>
  38 #include <gst/app/gstappsrc.h>
  39 #include <gst/gstatomicqueue.h>
  40
  41 struct decoder_sys_t
  42 {
  43     GstElement *p_decoder;
  44     GstElement *p_decode_src;
  45     GstElement *p_decode_in;
  46     GstElement *p_decode_out;
  47
  48     GstBus *p_bus;
  49
  50     GstVideoInfo vinfo;
  51     GstAtomicQueue *p_que;
  52     bool b_prerolled;
  53     bool b_running;
  54 };
  55
  56 typedef struct
  57 {
  58     GstCaps *p_sinkcaps;
  59     GstCaps *p_srccaps;
  60 } sink_src_caps_t;
  61
  62 /*****************************************************************************
  63  * Local prototypes
  64  *****************************************************************************/
  65 static int  OpenDecoder( vlc_object_t* );
  66 static void CloseDecoder( vlc_object_t* );
  67 static picture_t *DecodeBlock( decoder_t*, block_t** );
  68
  69 #define MODULE_DESCRIPTION N_( "Uses GStreamer framework's plugins " \
  70         "to decode the media codecs" )
  71
  72 #define USEDECODEBIN_TEXT N_( "Use DecodeBin" )
  73 #define USEDECODEBIN_LONGTEXT N_( \
  74     "DecodeBin is a container element, that can add and " \
  75     "manage multiple elements. Apart from adding the decoders, " \
  76     "decodebin also adds elementary stream parsers which can provide " \
  77     "more info such as codec profile, level and other attributes, " \
  78     "in the form of GstCaps (Stream Capabilities) to decoder." )
  79
  80 vlc_module_begin( )
  81     set_shortname( "GstDecode" )
  82     add_shortcut( "gstdecode" )
  83     set_category( CAT_INPUT )
  84     set_subcategory( SUBCAT_INPUT_VCODEC )
  85     /* decoder main module */
  86     set_description( N_( "GStreamer Based Decoder" ) )
  87     set_help( MODULE_DESCRIPTION )
  88     set_capability( "decoder", 50 )
  89     set_section( N_( "Decoding" ) , NULL )
  90     set_callbacks( OpenDecoder, CloseDecoder )
  91     add_bool( "use-decodebin", false, USEDECODEBIN_TEXT,
  92         USEDECODEBIN_LONGTEXT, false )
  93 vlc_module_end( )
  94
  95 /* gst_init( ) is not thread-safe, hence a thread-safe wrapper */
  96 static void vlc_gst_init( void )
  97 {
  98     static vlc_mutex_t init_lock = VLC_STATIC_MUTEX;
  99
 100     vlc_mutex_lock( &init_lock );
 101     gst_init( NULL, NULL );
 102     vlc_mutex_unlock( &init_lock );
 103 }
 104
 105 static GstStructure* vlc_to_gst_fmt( const es_format_t *p_fmt )
 106 {
 107     const video_format_t *p_vfmt = &p_fmt->video;
 108     GstStructure *p_str = NULL;
 109
 110     switch( p_fmt->i_codec ){
 111     case VLC_CODEC_H264:
 112         p_str = gst_structure_new_empty( "video/x-h264" );
 113         gst_structure_set( p_str, "alignment", G_TYPE_STRING, "au", NULL );
 114         break;
 115     case VLC_CODEC_MP4V:
 116         p_str = gst_structure_new_empty( "video/mpeg" );
 117         gst_structure_set( p_str, "mpegversion", G_TYPE_INT, 4,
 118                 "systemstream", G_TYPE_BOOLEAN, FALSE, NULL );
 119         break;
 120     case VLC_CODEC_VP8:
 121         p_str = gst_structure_new_empty( "video/x-vp8" );
 122         break;
 123     case VLC_CODEC_MPGV:
 124         p_str = gst_structure_new_empty( "video/mpeg" );
 125         gst_structure_set( p_str, "mpegversion", G_TYPE_INT, 2,
 126                 "systemstream", G_TYPE_BOOLEAN, FALSE, NULL );
 127         break;
 128     case VLC_CODEC_FLV1:
 129         p_str = gst_structure_new_empty( "video/x-flash-video" );
 130         gst_structure_set( p_str, "flvversion", G_TYPE_INT, 1, NULL );
 131         break;
 132     case VLC_CODEC_WMV1:
 133         p_str = gst_structure_new_empty( "video/x-wmv" );
 134         gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 1,
 135                 "format", G_TYPE_STRING, "WMV1", NULL );
 136         break;
 137     case VLC_CODEC_WMV2:
 138         p_str = gst_structure_new_empty( "video/x-wmv" );
 139         gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 2,
 140                 "format", G_TYPE_STRING, "WMV2", NULL );
 141         break;
 142     case VLC_CODEC_WMV3:
 143         p_str = gst_structure_new_empty( "video/x-wmv" );
 144         gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 3,
 145                 "format", G_TYPE_STRING, "WMV3", NULL );
 146         break;
 147     case VLC_CODEC_VC1:
 148         p_str = gst_structure_new_empty( "video/x-wmv" );
 149         gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 3,
 150                 "format", G_TYPE_STRING, "WVC1", NULL );
 151         break;
 152     default:
 153         /* unsupported codec */
 154         return NULL;
 155     }
 156
 157     if( p_vfmt->i_width && p_vfmt->i_height )
 158         gst_structure_set( p_str,
 159                 "width", G_TYPE_INT, p_vfmt->i_width,
 160                 "height", G_TYPE_INT, p_vfmt->i_height, NULL );
 161
 162     if( p_vfmt->i_frame_rate && p_vfmt->i_frame_rate_base )
 163         gst_structure_set( p_str, "framerate", GST_TYPE_FRACTION,
 164                 p_vfmt->i_frame_rate,
 165                 p_vfmt->i_frame_rate_base, NULL );
 166
 167     if( p_vfmt->i_sar_num && p_vfmt->i_sar_den )
 168         gst_structure_set( p_str, "pixel-aspect-ratio", GST_TYPE_FRACTION,
 169                 p_vfmt->i_sar_num,
 170                 p_vfmt->i_sar_den, NULL );
 171
 172     if( p_fmt->i_extra )
 173     {
 174         GstBuffer *p_buf;
 175
 176         p_buf = gst_buffer_new_wrapped_full( GST_MEMORY_FLAG_READONLY,
 177                 p_fmt->p_extra, p_fmt->i_extra, 0,
 178                 p_fmt->i_extra, NULL, NULL );
 179         if( p_buf == NULL )
 180         {
 181             gst_structure_free( p_str );
 182             return NULL;
 183         }
 184
 185         gst_structure_set( p_str, "codec_data", GST_TYPE_BUFFER, p_buf, NULL );
 186         gst_buffer_unref( p_buf );
 187     }
 188
 189     return p_str;
 190 }
 191
 192 /* Emitted by appsrc when serving a seek request.
 193  * Seek over here is only used for flushing the buffers.
 194  * Returns TRUE always, as the 'real' seek will be
 195  * done by VLC framework */
 196 static gboolean seek_data_cb( GstAppSrc *p_src, guint64 l_offset,
 197         gpointer p_data )
 198 {
 199     VLC_UNUSED( p_src );
 200     decoder_t *p_dec = p_data;
 201     msg_Dbg( p_dec, "appsrc seeking to %"G_GUINT64_FORMAT, l_offset );
 202     return TRUE;
 203 }
 204
 205 /* Emitted by decodebin when there are no more
 206  * outputs.This signal is not really necessary
 207  * to be connected. It is connected here for sanity
 208  * check only, just in-case something unexpected
 209  * happens inside decodebin in finding the appropriate
 210  * decoder, and it fails to emit PAD_ADDED signal */
 211 static void no_more_pads_cb( GstElement *p_ele, gpointer p_data )
 212 {
 213     VLC_UNUSED( p_ele );
 214     decoder_t *p_dec = p_data;
 215     decoder_sys_t *p_sys = p_dec->p_sys;
 216     GstPad *p_pad;
 217
 218     msg_Dbg( p_dec, "no more pads" );
 219
 220     p_pad = gst_element_get_static_pad( p_sys->p_decode_out,
 221             "sink" );
 222     if( !gst_pad_is_linked( p_pad ) )
 223     {
 224         msg_Err( p_dec, "failed to link decode out pad" );
 225         GST_ELEMENT_ERROR( p_sys->p_decoder, STREAM, FAILED,
 226                 ( "vlc stream error" ), NULL );
 227     }
 228
 229     gst_object_unref( p_pad );
 230 }
 231
 232 /* Sets the video output format */
 233 static bool set_vout_format( GstStructure* p_str,
 234         const es_format_t *restrict p_infmt, es_format_t *restrict p_outfmt )
 235 {
 236     video_format_t *p_voutfmt = &p_outfmt->video;
 237     const video_format_t *p_vinfmt = &p_infmt->video;
 238     gboolean b_ret;
 239
 240     /* We are interested in system memory raw buffers for now,
 241      * but support for opaque data formats can also be added.
 242      * For eg. when using HW decoders for zero-copy */
 243     p_outfmt->i_codec = vlc_fourcc_GetCodecFromString(
 244             VIDEO_ES,
 245             gst_structure_get_string( p_str, "format" ) );
 246     if( !p_outfmt->i_codec )
 247         return false;
 248
 249     gst_structure_get_int( p_str, "width", &p_voutfmt->i_width );
 250     gst_structure_get_int( p_str, "height", &p_voutfmt->i_height );
 251
 252     b_ret = gst_structure_get_fraction( p_str,
 253             "pixel-aspect-ratio",
 254             &p_voutfmt->i_sar_num,
 255             &p_voutfmt->i_sar_den );
 256
 257     if( !b_ret || !p_voutfmt->i_sar_num ||
 258             !p_voutfmt->i_sar_den )
 259     {
 260         p_voutfmt->i_sar_num = 1;
 261         p_voutfmt->i_sar_den = 1;
 262     }
 263
 264     b_ret = gst_structure_get_fraction( p_str, "framerate",
 265             &p_voutfmt->i_frame_rate,
 266             &p_voutfmt->i_frame_rate_base );
 267
 268     if( !b_ret || !p_voutfmt->i_frame_rate ||
 269             !p_voutfmt->i_frame_rate_base )
 270     {
 271         p_voutfmt->i_frame_rate = p_vinfmt->i_frame_rate;
 272         p_voutfmt->i_frame_rate_base = p_vinfmt->i_frame_rate_base;
 273     }
 274
 275     return true;
 276 }
 277
 278 static bool set_out_fmt( decoder_t *p_dec, GstPad *p_pad )
 279 {
 280     GstCaps *p_caps = gst_pad_get_current_caps( p_pad );
 281     decoder_sys_t *p_sys = p_dec->p_sys;
 282     GstStructure *p_str;
 283
 284     if( !gst_video_info_from_caps( &p_sys->vinfo,
 285                 p_caps ) )
 286     {
 287         msg_Err( p_dec, "failed to get video info from caps" );
 288         gst_caps_unref( p_caps );
 289         GST_ELEMENT_ERROR( p_sys->p_decoder, STREAM, FAILED,
 290                 ( "vlc stream error" ), NULL );
 291         return false;
 292     }
 293
 294     p_str = gst_caps_get_structure( p_caps, 0 );
 295
 296     if( !set_vout_format( p_str, &p_dec->fmt_in, &p_dec->fmt_out ) )
 297     {
 298         msg_Err( p_dec, "failed to set out format" );
 299         gst_caps_unref( p_caps );
 300         GST_ELEMENT_ERROR( p_sys->p_decoder, STREAM, FAILED,
 301                 ( "vlc stream error" ), NULL );
 302         return false;
 303     }
 304
 305     gst_caps_unref( p_caps );
 306     return true;
 307 }
 308
 309 /* Emitted by decodebin and links decodebin to fakesink.
 310  * Since only one elementary codec stream is fed to decodebin,
 311  * this signal cannot be emitted more than once. */
 312 static void pad_added_cb( GstElement *p_ele, GstPad *p_pad, gpointer p_data )
 313 {
 314     VLC_UNUSED( p_ele );
 315     decoder_t *p_dec = p_data;
 316     decoder_sys_t *p_sys = p_dec->p_sys;
 317
 318     if( likely( gst_pad_has_current_caps( p_pad ) ) )
 319     {
 320         GstPad *p_sinkpad;
 321
 322         if( !set_out_fmt( p_dec, p_pad ) )
 323             return;
 324
 325         p_sinkpad = gst_element_get_static_pad(
 326                 p_sys->p_decode_out, "sink" );
 327         gst_pad_link( p_pad, p_sinkpad );
 328         gst_object_unref( p_sinkpad );
 329     }
 330     else
 331     {
 332         msg_Err( p_dec, "decodebin src pad has no caps" );
 333         GST_ELEMENT_ERROR( p_sys->p_decoder, STREAM, FAILED,
 334                 ( "vlc stream error" ), NULL );
 335     }
 336 }
 337
 338 /* Emitted by fakesink for every buffer and sets the
 339  * output format (if not set). Adds the buffer to the queue */
 340 static void frame_handoff_cb( GstElement *p_ele, GstBuffer *p_buf,
 341         GstPad *p_pad, gpointer p_data )
 342 {
 343     VLC_UNUSED( p_ele );
 344     decoder_t *p_dec = p_data;
 345     decoder_sys_t *p_sys = p_dec->p_sys;
 346
 347     if( unlikely( p_dec->fmt_out.i_codec == 0 ) )
 348     {
 349         if( !gst_pad_has_current_caps( p_pad ) )
 350         {
 351             msg_Err( p_dec, "fakesink pad has no caps" );
 352             GST_ELEMENT_ERROR( p_sys->p_decoder, STREAM, FAILED,
 353                     ( "vlc stream error" ), NULL );
 354             return;
 355         }
 356
 357         if( !set_out_fmt( p_dec, p_pad ) )
 358             return;
 359     }
 360
 361     /* Push the buffer to the queue */
 362     gst_atomic_queue_push( p_sys->p_que, gst_buffer_ref( p_buf ) );
 363 }
 364
 365 /* Copy the frame data from the GstBuffer (from decoder)
 366  * to the picture obtained from downstream in VLC.
 367  * TODO(Zero-Copy): This function should be avoided as much
 368  * as possible, since it involves a complete frame copy. */
 369 static void gst_CopyPicture( picture_t *p_pic, GstVideoFrame *p_frame )
 370 {
 371     int i_plane, i_planes, i_line, i_dst_stride, i_src_stride;
 372     uint8_t *p_dst, *p_src;
 373     int i_w, i_h;
 374
 375     i_planes = p_pic->i_planes;
 376     for( i_plane = 0; i_plane < i_planes; i_plane++ )
 377     {
 378         p_dst = p_pic->p[i_plane].p_pixels;
 379         p_src = GST_VIDEO_FRAME_PLANE_DATA( p_frame, i_plane );
 380         i_dst_stride = p_pic->p[i_plane].i_pitch;
 381         i_src_stride = GST_VIDEO_FRAME_PLANE_STRIDE( p_frame, i_plane );
 382
 383         i_w = GST_VIDEO_FRAME_COMP_WIDTH( p_frame,
 384                 i_plane ) * GST_VIDEO_FRAME_COMP_PSTRIDE( p_frame, i_plane );
 385         i_h = GST_VIDEO_FRAME_COMP_HEIGHT( p_frame, i_plane );
 386
 387         for( i_line = 0;
 388                 i_line < __MIN( p_pic->p[i_plane].i_lines, i_h );
 389                 i_line++ )
 390         {
 391             memcpy( p_dst, p_src, i_w );
 392             p_src += i_src_stride;
 393             p_dst += i_dst_stride;
 394         }
 395     }
 396 }
 397
 398 /* Check if the element can use this caps */
 399 static gint find_decoder_func( gconstpointer p_p1, gconstpointer p_p2 )
 400 {
 401     GstElementFactory *p_factory;
 402     sink_src_caps_t *p_caps;
 403
 404     p_factory = ( GstElementFactory* )p_p1;
 405     p_caps = ( sink_src_caps_t* )p_p2;
 406
 407     return !( gst_element_factory_can_sink_any_caps( p_factory,
 408                 p_caps->p_sinkcaps ) &&
 409             gst_element_factory_can_src_any_caps( p_factory,
 410                 p_caps->p_srccaps ) );
 411 }
 412
 413 static bool default_msg_handler( decoder_t *p_dec, GstMessage *p_msg )
 414 {
 415     bool err = false;
 416
 417     switch( GST_MESSAGE_TYPE( p_msg ) ){
 418     case GST_MESSAGE_ERROR:
 419         {
 420             gchar  *psz_debug;
 421             GError *p_error;
 422
 423             gst_message_parse_error( p_msg, &p_error, &psz_debug );
 424             g_free( psz_debug );
 425
 426             msg_Err( p_dec, "Error from %s: %s",
 427                     GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
 428                     p_error->message );
 429             g_error_free( p_error );
 430             err = true;
 431         }
 432         break;
 433     case GST_MESSAGE_WARNING:
 434         {
 435             gchar  *psz_debug;
 436             GError *p_error;
 437
 438             gst_message_parse_warning( p_msg, &p_error, &psz_debug );
 439             g_free( psz_debug );
 440
 441             msg_Warn( p_dec, "Warning from %s: %s",
 442                     GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
 443                     p_error->message );
 444             g_error_free( p_error );
 445         }
 446         break;
 447     case GST_MESSAGE_INFO:
 448         {
 449             gchar  *psz_debug;
 450             GError *p_error;
 451
 452             gst_message_parse_info( p_msg, &p_error, &psz_debug );
 453             g_free( psz_debug );
 454
 455             msg_Info( p_dec, "Info from %s: %s",
 456                     GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
 457                     p_error->message );
 458             g_error_free( p_error );
 459         }
 460         break;
 461     default:
 462         break;
 463     }
 464
 465     return err;
 466 }
 467
 468 /*****************************************************************************
 469  * OpenDecoder: probe the decoder and return score
 470  *****************************************************************************/
 471 static int OpenDecoder( vlc_object_t *p_this )
 472 {
 473     decoder_t *p_dec = ( decoder_t* )p_this;
 474     decoder_sys_t *p_sys;
 475     GstStateChangeReturn i_ret;
 476     gboolean b_ret;
 477     sink_src_caps_t caps = { NULL, NULL };
 478     GstStructure *p_str;
 479     GstAppSrcCallbacks cb;
 480     int i_rval = VLC_SUCCESS;
 481     GList *p_list;
 482     bool dbin;
 483
 484 #define VLC_GST_CHECK( r, v, s, t ) \
 485     { if( r == v ){ msg_Err( p_dec, s ); i_rval = t; goto fail; } }
 486
 487     vlc_gst_init( );
 488
 489     p_str = vlc_to_gst_fmt( &p_dec->fmt_in );
 490     if( !p_str )
 491         return VLC_EGENERIC;
 492
 493     /* Allocate the memory needed to store the decoder's structure */
 494     p_sys = p_dec->p_sys = calloc( 1, sizeof( *p_sys ) );
 495     if( p_sys == NULL )
 496     {
 497         gst_structure_free( p_str );
 498         return VLC_ENOMEM;
 499     }
 500
 501     dbin = var_CreateGetBool( p_dec, "use-decodebin" );
 502     msg_Dbg( p_dec, "Using decodebin? %s", dbin ? "yes ":"no" );
 503
 504     caps.p_sinkcaps = gst_caps_new_empty( );
 505     gst_caps_append_structure( caps.p_sinkcaps, p_str );
 506     /* Currently supports only system memory raw output format */
 507     caps.p_srccaps = gst_caps_new_empty_simple( "video/x-raw" );
 508
 509     /* Get the list of all the available gstreamer decoders */
 510     p_list = gst_element_factory_list_get_elements(
 511             GST_ELEMENT_FACTORY_TYPE_DECODER, GST_RANK_MARGINAL );
 512     VLC_GST_CHECK( p_list, NULL, "no decoder list found", VLC_ENOMOD );
 513     if( !dbin )
 514     {
 515         GList *p_l;
 516         /* Sort them as per ranks */
 517         p_list = g_list_sort( p_list, gst_plugin_feature_rank_compare_func );
 518         VLC_GST_CHECK( p_list, NULL, "failed to sort decoders list",
 519                 VLC_ENOMOD );
 520         p_l = g_list_find_custom( p_list, &caps, find_decoder_func );
 521         VLC_GST_CHECK( p_l, NULL, "no suitable decoder found",
 522                 VLC_ENOMOD );
 523         /* create the decoder with highest rank */
 524         p_sys->p_decode_in = gst_element_factory_create(
 525                 ( GstElementFactory* )p_l->data, NULL );
 526         VLC_GST_CHECK( p_sys->p_decode_in, NULL,
 527                 "failed to create decoder", VLC_ENOMOD );
 528     }
 529     else
 530     {
 531         GList *p_l;
 532         /* Just check if any suitable decoder exists, rest will be
 533          * handled by decodebin */
 534         p_l = g_list_find_custom( p_list, &caps, find_decoder_func );
 535         VLC_GST_CHECK( p_l, NULL, "no suitable decoder found",
 536                 VLC_ENOMOD );
 537     }
 538     gst_plugin_feature_list_free( p_list );
 539     p_list = NULL;
 540     gst_caps_unref( caps.p_srccaps );
 541     caps.p_srccaps = NULL;
 542
 543     p_sys->b_prerolled = false;
 544     p_sys->b_running = false;
 545
 546     /* Queue: GStreamer thread will dump buffers into this queue,
 547      * DecodeBlock() will pop out the buffers from the queue */
 548     p_sys->p_que = gst_atomic_queue_new( 0 );
 549     VLC_GST_CHECK( p_sys->p_que, NULL, "failed to create queue",
 550             VLC_ENOMEM );
 551
 552     p_sys->p_decode_src = gst_element_factory_make( "appsrc", NULL );
 553     VLC_GST_CHECK( p_sys->p_decode_src, NULL, "appsrc not found",
 554             VLC_ENOMOD );
 555     g_object_set( G_OBJECT( p_sys->p_decode_src ), "caps", caps.p_sinkcaps,
 556             "block", FALSE, "emit-signals", TRUE, "format", GST_FORMAT_BYTES,
 557             "stream-type", GST_APP_STREAM_TYPE_SEEKABLE,
 558             /* Making DecodeBlock() to block on appsrc with max queue size of 1 byte.
 559              * This will make the push_buffer() tightly coupled with the buffer
 560              * flow from appsrc -> decoder. push_buffer() will only return when
 561              * the same buffer it just fed to appsrc has also been fed to the
 562              * decoder element as well */
 563             "block", TRUE, "max-bytes", ( guint64 )1, NULL );
 564     gst_caps_unref( caps.p_sinkcaps );
 565     caps.p_sinkcaps = NULL;
 566     cb.enough_data = cb.need_data = NULL;
 567     cb.seek_data = seek_data_cb;
 568     gst_app_src_set_callbacks( GST_APP_SRC( p_sys->p_decode_src ),
 569             &cb, p_dec, NULL );
 570
 571     if( dbin )
 572     {
 573         p_sys->p_decode_in = gst_element_factory_make( "decodebin", NULL );
 574         VLC_GST_CHECK( p_sys->p_decode_in, NULL, "decodebin not found",
 575                 VLC_ENOMOD );
 576         //g_object_set( G_OBJECT( p_sys->p_decode_in ),
 577         //"max-size-buffers", 2, NULL );
 578         g_signal_connect( G_OBJECT( p_sys->p_decode_in ), "pad-added",
 579                 G_CALLBACK( pad_added_cb ), p_dec );
 580         g_signal_connect( G_OBJECT( p_sys->p_decode_in ), "no-more-pads",
 581                 G_CALLBACK( no_more_pads_cb ), p_dec );
 582     }
 583
 584     /* fakesink: will emit signal for every available buffer */
 585     p_sys->p_decode_out = gst_element_factory_make( "fakesink", NULL );
 586     VLC_GST_CHECK( p_sys->p_decode_out, NULL, "fakesink not found",
 587             VLC_ENOMOD );
 588     /* connect to the signal with the callback */
 589     g_object_set( G_OBJECT( p_sys->p_decode_out ), "sync", FALSE,
 590             "enable-last-sample", FALSE, "signal-handoffs", TRUE, NULL );
 591     g_signal_connect( G_OBJECT( p_sys->p_decode_out ), "handoff",
 592             G_CALLBACK( frame_handoff_cb ), p_dec );
 593
 594     p_sys->p_decoder = GST_ELEMENT( gst_bin_new( "decoder" ) );
 595     VLC_GST_CHECK( p_sys->p_decoder, NULL, "bin not found", VLC_ENOMOD );
 596     p_sys->p_bus = gst_bus_new( );
 597     VLC_GST_CHECK( p_sys->p_bus, NULL, "failed to create bus",
 598             VLC_ENOMOD );
 599     gst_element_set_bus( p_sys->p_decoder, p_sys->p_bus );
 600
 601     gst_bin_add_many( GST_BIN( p_sys->p_decoder ),
 602             p_sys->p_decode_src, p_sys->p_decode_in,
 603             p_sys->p_decode_out, NULL );
 604     gst_object_ref( p_sys->p_decode_src );
 605     gst_object_ref( p_sys->p_decode_in );
 606     gst_object_ref( p_sys->p_decode_out );
 607
 608     b_ret = gst_element_link( p_sys->p_decode_src, p_sys->p_decode_in );
 609     VLC_GST_CHECK( b_ret, FALSE, "failed to link src <-> in",
 610             VLC_EGENERIC );
 611
 612     if( !dbin )
 613     {
 614         b_ret = gst_element_link( p_sys->p_decode_in, p_sys->p_decode_out );
 615         VLC_GST_CHECK( b_ret, FALSE, "failed to link in <-> out",
 616                 VLC_EGENERIC );
 617     }
 618
 619     p_dec->fmt_out.i_cat = p_dec->fmt_in.i_cat;
 620
 621     /* set the pipeline to playing */
 622     i_ret = gst_element_set_state( p_sys->p_decoder, GST_STATE_PLAYING );
 623     VLC_GST_CHECK( i_ret, GST_STATE_CHANGE_FAILURE,
 624             "set state failure", VLC_EGENERIC );
 625     p_sys->b_running = true;
 626
 627     /* Set callbacks */
 628     p_dec->pf_decode_video = DecodeBlock;
 629
 630     return VLC_SUCCESS;
 631
 632 fail:
 633     if( caps.p_sinkcaps )
 634         gst_caps_unref( caps.p_sinkcaps );
 635     if( caps.p_srccaps )
 636         gst_caps_unref( caps.p_srccaps );
 637     if( p_list )
 638         gst_plugin_feature_list_free( p_list );
 639     CloseDecoder( ( vlc_object_t* )p_dec );
 640     return i_rval;
 641 }
 642
 643 /* Decode */
 644 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 645 {
 646     block_t *p_block;
 647     picture_t *p_pic = NULL;
 648     decoder_sys_t *p_sys = p_dec->p_sys;
 649     GstMessage *p_msg;
 650     gboolean b_ret;
 651     GstBuffer *p_buf;
 652
 653     if( !pp_block )
 654         return NULL;
 655
 656     p_block = *pp_block;
 657
 658     if( !p_block )
 659         goto check_messages;
 660
 661     if( unlikely( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY |
 662                     BLOCK_FLAG_CORRUPTED ) ) )
 663     {
 664         if( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
 665         {
 666             GstBuffer *p_buffer;
 667             /* Send a new segment event. Seeking position is
 668              * irrelevant in this case, as the main motive for a
 669              * seek here, is to tell the elements to start flushing
 670              * and start accepting buffers from a new time segment */
 671             b_ret = gst_element_seek_simple( p_sys->p_decoder,
 672                     GST_FORMAT_BYTES, GST_SEEK_FLAG_FLUSH, 0 );
 673             msg_Dbg( p_dec, "new segment event : %d", b_ret );
 674
 675             /* flush the output buffers from the queue */
 676             while( ( p_buffer = gst_atomic_queue_pop( p_sys->p_que ) ) )
 677                 gst_buffer_unref( p_buffer );
 678
 679             p_sys->b_prerolled = false;
 680         }
 681
 682         block_Release( p_block );
 683         goto done;
 684     }
 685
 686     if( likely( p_block->i_buffer ) )
 687     {
 688         p_buf = gst_buffer_new_wrapped_full( GST_MEMORY_FLAG_READONLY,
 689                 p_block->p_start, p_block->i_size,
 690                 p_block->p_buffer - p_block->p_start, p_block->i_buffer,
 691                 p_block, ( GDestroyNotify )block_Release );
 692         if( unlikely( p_buf == NULL ) )
 693         {
 694             msg_Err( p_dec, "failed to create input gstbuffer" );
 695             p_dec->b_error = true;
 696             block_Release( p_block );
 697             goto done;
 698         }
 699
 700         if( p_block->i_dts > VLC_TS_INVALID )
 701             GST_BUFFER_DTS( p_buf ) = gst_util_uint64_scale( p_block->i_dts,
 702                     GST_SECOND, GST_MSECOND );
 703
 704         if( p_block->i_pts <= VLC_TS_INVALID )
 705             GST_BUFFER_PTS( p_buf ) = GST_BUFFER_DTS( p_buf );
 706         else
 707             GST_BUFFER_PTS( p_buf ) = gst_util_uint64_scale( p_block->i_pts,
 708                     GST_SECOND, GST_MSECOND );
 709
 710         if( p_block->i_length > VLC_TS_INVALID )
 711             GST_BUFFER_DURATION( p_buf ) = gst_util_uint64_scale(
 712                     p_block->i_length, GST_SECOND, GST_MSECOND );
 713
 714         if( p_dec->fmt_in.video.i_frame_rate  &&
 715                 p_dec->fmt_in.video.i_frame_rate_base )
 716             GST_BUFFER_DURATION( p_buf ) = gst_util_uint64_scale( GST_SECOND,
 717                     p_dec->fmt_in.video.i_frame_rate_base,
 718                     p_dec->fmt_in.video.i_frame_rate );
 719
 720         /* Give the input buffer to GStreamer Bin.
 721          *
 722          *  libvlc                      libvlc
 723          *    \ (i/p)              (o/p) ^
 724          *     \                        /
 725          *   ___v____GSTREAMER BIN_____/____
 726          *  |                               |
 727          *  |   appsrc-->decode-->fakesink  |
 728          *  |_______________________________|
 729          *
 730          * * * * * * * * * * * * * * * * * * * * */
 731         if( unlikely( gst_app_src_push_buffer(
 732                         GST_APP_SRC_CAST( p_sys->p_decode_src ), p_buf )
 733                     != GST_FLOW_OK ) )
 734         {
 735             /* block will be released internally,
 736              * when gst_buffer_unref() is called */
 737             p_dec->b_error = true;
 738             msg_Err( p_dec, "failed to push buffer" );
 739             goto done;
 740         }
 741     }
 742     else
 743         block_Release( p_block );
 744
 745 check_messages:
 746     /* Poll for any messages, errors */
 747     p_msg = gst_bus_pop_filtered( p_sys->p_bus,
 748             GST_MESSAGE_ASYNC_DONE | GST_MESSAGE_ERROR |
 749             GST_MESSAGE_EOS | GST_MESSAGE_WARNING |
 750             GST_MESSAGE_INFO );
 751     if( p_msg )
 752     {
 753         switch( GST_MESSAGE_TYPE( p_msg ) ){
 754         case GST_MESSAGE_EOS:
 755             /* for debugging purpose */
 756             msg_Warn( p_dec, "got unexpected eos" );
 757             break;
 758         /* First buffer received */
 759         case GST_MESSAGE_ASYNC_DONE:
 760             /* for debugging purpose */
 761             p_sys->b_prerolled = true;
 762             msg_Dbg( p_dec, "Pipeline is prerolled" );
 763             break;
 764         default:
 765             p_dec->b_error = default_msg_handler( p_dec, p_msg );
 766             if( p_dec->b_error )
 767             {
 768                 gst_message_unref( p_msg );
 769                 goto done;
 770             }
 771             break;
 772         }
 773         gst_message_unref( p_msg );
 774     }
 775
 776     /* Look for any output buffers in the queue */
 777     if( gst_atomic_queue_peek( p_sys->p_que ) )
 778     {
 779         GstVideoFrame frame;
 780
 781         /* Get a new picture */
 782         p_pic = decoder_NewPicture( p_dec );
 783         if( !p_pic )
 784             goto done;
 785
 786         p_buf = GST_BUFFER_CAST(
 787                 gst_atomic_queue_pop( p_sys->p_que ) );
 788
 789         if( likely( GST_BUFFER_PTS_IS_VALID( p_buf ) ) )
 790             p_pic->date = gst_util_uint64_scale(
 791                     GST_BUFFER_PTS( p_buf ), GST_MSECOND, GST_SECOND );
 792         else
 793             msg_Warn( p_dec, "Gst Buffer has no timestamp" );
 794
 795         if( unlikely( !gst_video_frame_map( &frame,
 796                         &p_sys->vinfo, p_buf, GST_MAP_READ ) ) )
 797         {
 798             msg_Err( p_dec, "failed to map gst video frame" );
 799             gst_buffer_unref( p_buf );
 800             p_dec->b_error = true;
 801             goto done;
 802         }
 803
 804         gst_CopyPicture( p_pic, &frame );
 805         gst_video_frame_unmap( &frame );
 806         gst_buffer_unref( p_buf );
 807     }
 808
 809 done:
 810     *pp_block = NULL;
 811     return p_pic;
 812 }
 813
 814 /* Close the decoder instance */
 815 static void CloseDecoder( vlc_object_t *p_this )
 816 {
 817     decoder_t *p_dec = ( decoder_t* )p_this;
 818     decoder_sys_t *p_sys = p_dec->p_sys;
 819
 820     if( p_sys->b_running )
 821     {
 822         GstMessage *p_msg;
 823         GstFlowReturn i_ret;
 824
 825         /* Send EOS to the pipeline */
 826         i_ret = gst_app_src_end_of_stream(
 827                 GST_APP_SRC_CAST( p_sys->p_decode_src ) );
 828         msg_Dbg( p_dec, "app src eos: %s", gst_flow_get_name( i_ret ) );
 829
 830         /* and catch it on the bus with a timeout */
 831         p_msg = gst_bus_timed_pop_filtered( p_sys->p_bus,
 832                 2000000000ULL, GST_MESSAGE_EOS | GST_MESSAGE_ERROR );
 833
 834         if( p_msg )
 835         {
 836             switch( GST_MESSAGE_TYPE( p_msg ) ){
 837             case GST_MESSAGE_EOS:
 838                 msg_Dbg( p_dec, "got eos" );
 839                 break;
 840             default:
 841                 p_dec->b_error = default_msg_handler( p_dec, p_msg );
 842                 if( p_dec->b_error )
 843                     msg_Warn( p_dec, "pipeline may not close gracefully" );
 844                 break;
 845             }
 846
 847             gst_message_unref( p_msg );
 848         }
 849         else
 850             msg_Warn( p_dec,
 851                     "no message, pipeline may not close gracefully" );
 852     }
 853
 854     /* Remove any left-over buffers from the queue */
 855     if( p_sys->p_que )
 856     {
 857         GstBuffer *p_buf;
 858         while( ( p_buf = gst_atomic_queue_pop( p_sys->p_que ) ) )
 859             gst_buffer_unref( p_buf );
 860         gst_atomic_queue_unref( p_sys->p_que );
 861     }
 862
 863     if( p_sys->b_running &&
 864             gst_element_set_state( p_sys->p_decoder, GST_STATE_NULL )
 865             != GST_STATE_CHANGE_SUCCESS )
 866         msg_Warn( p_dec,
 867                 "failed to change the state to NULL," \
 868                 "pipeline may not close gracefully" );
 869
 870     if( p_sys->p_bus )
 871         gst_object_unref( p_sys->p_bus );
 872     if( p_sys->p_decode_src )
 873         gst_object_unref( p_sys->p_decode_src );
 874     if( p_sys->p_decode_in )
 875         gst_object_unref( p_sys->p_decode_in );
 876     if( p_sys->p_decode_out )
 877         gst_object_unref( p_sys->p_decode_out );
 878     if( p_sys->p_decoder )
 879         gst_object_unref( p_sys->p_decoder );
 880
 881     free( p_sys );
 882 }