[vlc-devel] [PATCH 1/2] DASH: implement Seek()
Hugo Beauzée-Luyssen
beauze.h at gmail.com
Wed Mar 28 18:06:34 CEST 2012
2012/3/26 Frédéric Yhuel <fyhuel at viotech.net>:
> 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;
You are checking for an UINT overflow, but are assigning into an int.
> + 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;
Same remark applies here.
> + 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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Seems ok otherwise!
Regards,
--
Hugo Beauzée-Luyssen
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