[vlc-devel] [PATCH 1/2] DASH: implement Seek()
Frédéric Yhuel
fyhuel at viotech.net
Mon Mar 26 16:38:46 CEST 2012
This is needed for DASH module to work with (not yet ready) VLC MP4
demux. Forward seeking is implemented by calling Read() with a NULL
argument (= skipping), while backward seeking is limited to the current
block in the block_bytestream_t upon which is built the internal buffer.
This limitation is not really a problem because backward seeking will be
needed only for the parsing of the initialization fragment.
---
modules/stream_filter/dash/DASHManager.cpp | 5 ++
modules/stream_filter/dash/DASHManager.h | 1 +
modules/stream_filter/dash/buffer/BlockBuffer.cpp | 16 ++++++
modules/stream_filter/dash/buffer/BlockBuffer.h | 1 +
modules/stream_filter/dash/dash.cpp | 53 ++++++++++++++++++++-
5 files changed, 74 insertions(+), 2 deletions(-)
diff --git a/modules/stream_filter/dash/DASHManager.cpp b/modules/stream_filter/dash/DASHManager.cpp
index f649015..8483c9d 100644
--- a/modules/stream_filter/dash/DASHManager.cpp
+++ b/modules/stream_filter/dash/DASHManager.cpp
@@ -74,6 +74,11 @@ int DASHManager::read( void *p_buffer, size_t len )
return this->buffer->get(p_buffer, len);
}
+int DASHManager::seekBackwards( unsigned i_len )
+{
+ return this->buffer->seekBackwards( i_len );
+}
+
int DASHManager::peek( const uint8_t **pp_peek, size_t i_peek )
{
return this->buffer->peek(pp_peek, i_peek);
diff --git a/modules/stream_filter/dash/DASHManager.h b/modules/stream_filter/dash/DASHManager.h
index a09e98e..90d9317 100644
--- a/modules/stream_filter/dash/DASHManager.h
+++ b/modules/stream_filter/dash/DASHManager.h
@@ -47,6 +47,7 @@ namespace dash
bool start ();
int read ( void *p_buffer, size_t len );
int peek ( const uint8_t **pp_peek, size_t i_peek );
+ int seekBackwards ( unsigned len );
const mpd::IMPDManager* getMpdManager () const;
const logic::IAdaptationLogic* getAdaptionLogic() const;
diff --git a/modules/stream_filter/dash/buffer/BlockBuffer.cpp b/modules/stream_filter/dash/buffer/BlockBuffer.cpp
index 056c481..1db9168 100644
--- a/modules/stream_filter/dash/buffer/BlockBuffer.cpp
+++ b/modules/stream_filter/dash/buffer/BlockBuffer.cpp
@@ -85,6 +85,22 @@ int BlockBuffer::peek (const uint8_t **pp_peek, unsigned int
vlc_mutex_unlock(&this->monitorMutex);
return ret;
}
+
+int BlockBuffer::seekBackwards (unsigned len)
+{
+ vlc_mutex_lock(&this->monitorMutex);
+ if( this->buffer.i_offset > len )
+ {
+ this->buffer.i_offset -= len;
+ this->sizeBytes += len;
+ vlc_mutex_unlock(&this->monitorMutex);
+ return VLC_SUCCESS;
+ }
+
+ vlc_mutex_unlock(&this->monitorMutex);
+ return VLC_EGENERIC;
+}
+
int BlockBuffer::get (void *p_data, unsigned int len)
{
vlc_mutex_lock(&this->monitorMutex);
diff --git a/modules/stream_filter/dash/buffer/BlockBuffer.h b/modules/stream_filter/dash/buffer/BlockBuffer.h
index 570861f..2c39db1 100644
--- a/modules/stream_filter/dash/buffer/BlockBuffer.h
+++ b/modules/stream_filter/dash/buffer/BlockBuffer.h
@@ -49,6 +49,7 @@ namespace dash
void put (block_t *block);
int get (void *p_data, unsigned int len);
int peek (const uint8_t **pp_peek, unsigned int i_peek);
+ int seekBackwards (unsigned len);
void setEOF (bool value);
bool getEOF ();
mtime_t size ();
diff --git a/modules/stream_filter/dash/dash.cpp b/modules/stream_filter/dash/dash.cpp
index b503f27..9003a9d 100644
--- a/modules/stream_filter/dash/dash.cpp
+++ b/modules/stream_filter/dash/dash.cpp
@@ -77,7 +77,7 @@ struct stream_sys_t
dash::DASHManager *p_dashManager;
dash::http::HTTPConnectionManager *p_conManager;
dash::mpd::MPD *p_mpd;
- int position;
+ uint64_t position;
bool isLive;
};
@@ -160,6 +160,46 @@ static void Close(vlc_object_t *p_obj)
/*****************************************************************************
* Callbacks:
*****************************************************************************/
+static int Seek ( stream_t *p_stream, uint64_t pos )
+{
+ stream_sys_t *p_sys = (stream_sys_t *) p_stream->p_sys;
+ dash::DASHManager *p_dashManager = p_sys->p_dashManager;
+ int i_ret = 0;
+ unsigned i_len = 0;
+ long i_read = 0;
+
+ if( pos < p_sys->position )
+ {
+ if( p_sys->position - pos > UINT_MAX )
+ {
+ msg_Err( p_stream, "Cannot seek backward that far!" );
+ return VLC_EGENERIC;
+ }
+ i_len = p_sys->position - pos;
+ i_ret = p_dashManager->seekBackwards( i_len );
+ if( i_ret == VLC_EGENERIC )
+ {
+ msg_Err( p_stream, "Cannot seek backward outside the current block :-/" );
+ return VLC_EGENERIC;
+ }
+ else
+ return VLC_SUCCESS;
+ }
+
+ /* Seek forward */
+ if( pos - p_sys->position > UINT_MAX )
+ {
+ msg_Err( p_stream, "Cannot seek forward that far!" );
+ return VLC_EGENERIC;
+ }
+ i_len = pos - p_sys->position;
+ i_read = Read( p_stream, (void *)NULL, i_len );
+ if( (unsigned)i_read == i_len )
+ return VLC_SUCCESS;
+ else
+ return VLC_EGENERIC;
+}
+
static int Read (stream_t *p_stream, void *p_ptr, unsigned int i_len)
{
stream_sys_t *p_sys = (stream_sys_t *) p_stream->p_sys;
@@ -221,7 +261,16 @@ static int Control (stream_t *p_stream, int i_query, va_list args)
*(va_arg (args, uint64_t *)) = p_sys->position;
break;
case STREAM_SET_POSITION:
- return VLC_EGENERIC;
+ {
+ uint64_t pos = (uint64_t)va_arg(args, uint64_t);
+ if(Seek(p_stream, pos) == VLC_SUCCESS)
+ {
+ p_sys->position = pos;
+ break;
+ }
+ else
+ return VLC_EGENERIC;
+ }
case STREAM_GET_SIZE:
{
uint64_t* res = (va_arg (args, uint64_t *));
--
1.7.5.4
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