[vlc-devel] [PATCH] [RFC] add demux filters that are similar in API to regular demuxers
Rémi Denis-Courmont
remi at remlab.net
Sun Jun 5 14:15:41 CEST 2016
Le 2016-06-05 13:03, Steve Lhomme a écrit :
> The only difference is that when control/demux callbacks are called,
> they are
> given the next demuxers to call in the chain
>
> --
> replaces https://patches.videolan.org/patch/13585/
> and https://patches.videolan.org/patch/13615/ with legacy patch
> remaining
> I do not understand how some demuxers have pf_demux to NULL, so there
> might be
> some simplifications possible.
> ---
> NEWS | 3 ++
> include/vlc_demux.h | 12 ++++++
> src/input/demux.c | 106
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> src/input/demux.h | 3 ++
> src/input/input.c | 9 +++++
> src/input/var.c | 1 +
> src/libvlc-module.c | 5 +++
> src/playlist/engine.c | 1 +
> 8 files changed, 140 insertions(+)
>
> diff --git a/NEWS b/NEWS
> index fd5e690..b6eeb06 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -101,6 +101,9 @@ Stream filter:
> * Added stream prebuffering plugin
> * Removed HTTP Live streaming stream filter
> * Added zlib (a.k.a. deflate) decompression filter
> +
> +Demux filter:
> + * Added a demuxer filter chain to filter or intercept control
> commands and demuxing
>
> Audio output:
> * Complete rewrite of the AudioTrack Android module. This is now
> the default.
> diff --git a/include/vlc_demux.h b/include/vlc_demux.h
> index 1153e1c..0c4bfeb 100644
> --- a/include/vlc_demux.h
> +++ b/include/vlc_demux.h
> @@ -77,16 +77,25 @@ struct demux_t
>
> /* Weak link to parent input */
> input_thread_t *p_input;
> +
> + /* demux_t filter chaining */
> + demux_t *p_next;
> + demux_t *p_prev;
Should not be needed.
> + int (*pf_filter_demux) ( demux_t *p_this, demux_t *p_next );
Just use pf_demux. You can always access p_demux->p_next in the
function.
> };
>
> static inline void demux_InfoAddFlags( demux_t *p_demux, int flags )
> {
> p_demux->info.i_update |= flags;
> + if ( p_demux->p_prev )
> + demux_InfoAddFlags( p_demux->p_prev, flags );
> }
This can cause reentrancy issues.
>
> static inline void demux_InfoDelFlags( demux_t *p_demux, int flags )
> {
> p_demux->info.i_update &= ~flags;
> + if ( p_demux->p_prev )
> + demux_InfoDelFlags( p_demux->p_prev, flags );
> }
>
>
> @@ -325,6 +334,9 @@ VLC_API int demux_vaControlHelper( stream_t *,
> int64_t i_start, int64_t i_end,
>
> VLC_USED static inline int demux_Demux( demux_t *p_demux )
> {
> + if (p_demux->pf_filter_demux)
> + return p_demux->pf_filter_demux( p_demux, p_demux->p_next );
> +
Should not be needed.
> if( !p_demux->pf_demux )
> return VLC_DEMUXER_SUCCESS;
>
> diff --git a/src/input/demux.c b/src/input/demux.c
> index 303c0b8..6e59c3b 100644
> --- a/src/input/demux.c
> +++ b/src/input/demux.c
> @@ -133,6 +133,9 @@ demux_t *demux_NewAdvanced( vlc_object_t *p_obj,
> input_thread_t *p_parent_input,
>
> p_demux->pf_demux = NULL;
> p_demux->pf_control = NULL;
> + p_demux->pf_filter_demux = NULL;
> + p_demux->p_prev = NULL;
> + p_demux->p_next = NULL;
> p_demux->p_sys = NULL;
> p_demux->info.i_update = 0;
> p_demux->info.i_title = 0;
> @@ -342,6 +345,13 @@ void demux_Delete( demux_t *p_demux )
> {
> stream_t *s;
>
> + demux_t *p_next = p_demux->p_next;
> + if ( p_next != NULL )
> + {
> + p_next->s = NULL; /* demux fiters don't own the stream */
> + demux_Delete( p_next );
> + }
> +
> module_unneed( p_demux, p_demux->p_module );
> free( p_demux->psz_file );
> free( p_demux->psz_location );
> @@ -656,3 +666,99 @@ static bool SkipAPETag( demux_t *p_demux )
> return true;
> }
>
> +static demux_t *demux_FilterNew( demux_t *p_wrapped, const char
> *p_name )
> +{
> + demux_t *p_demux = vlc_custom_create( VLC_OBJECT( p_wrapped ),
> + sizeof( demux_t ),
> "demux_filter" );
> + if( unlikely(p_demux == NULL) )
> + return NULL;
> +
> + p_demux->pf_demux = p_wrapped->pf_demux; /* forwarded as
> it's tested for NULL */
> + p_demux->pf_control = p_wrapped->pf_control;
> + p_demux->pf_filter_demux = NULL;
> + p_demux->p_sys = NULL;
> + p_demux->s = p_wrapped->s;
> + p_demux->psz_access = NULL;
> + p_demux->psz_demux = NULL;
> + p_demux->psz_location = NULL;
> + p_demux->psz_file = NULL;
> + p_demux->p_input = p_wrapped->p_input;
> + p_demux->out = NULL;
> + p_demux->p_module =
> + module_need( p_demux, "demux_filter", p_name, p_name != NULL
> );
> +
> + if( p_demux->p_module == NULL )
> + goto error;
> +
> + assert(p_demux->pf_demux == p_wrapped->pf_demux); /* ensure the
> NULL test is kept */
> + p_wrapped->p_prev = p_demux;
> + p_demux->p_next = p_wrapped;
> +
> + return p_demux;
> +error:
> + vlc_object_release( p_demux );
> + return NULL;
> +}
> +
> +demux_t *demux_FilterChainNew( demux_t *p_demux, const char
> *psz_chain )
> +{
> + if( !psz_chain || !*psz_chain )
> + return NULL; /* add permanent filters */
> +
> + char *psz_parser = strdup(psz_chain);
> + if(!psz_parser)
> + return NULL;
> +
> + vlc_array_t name;
> + vlc_array_init(&name);
> +
> + /* parse chain */
> + while(psz_parser)
> + {
> + config_chain_t *p_cfg;
> + char *psz_name;
> + char *psz_rest_chain = config_ChainCreate( &psz_name,
> &p_cfg, psz_parser );
> + free( psz_parser );
> + psz_parser = psz_rest_chain;
> +
> + vlc_array_append(&name, psz_name);
> + config_ChainDestroy(p_cfg);
> + }
> +
> + int i = vlc_array_count(&name);
> + vlc_array_t module;
> + vlc_array_init(&module);
> + while(i--)
> + {
> + const char *p_name = vlc_array_item_at_index(&name, i);
> + demux_t *p_next = demux_FilterNew( p_demux, p_name );
> + if(!p_next)
> + goto error;
> +
> + vlc_array_append(&module, p_next);
> + p_demux = p_next;
> + }
> +
> + vlc_array_clear(&name);
> + vlc_array_clear(&module);
> +
> + return p_demux;
> + error:
> + i++; /* last module couldn't be created */
> +
> + /* destroy all modules created, starting with the last one */
> + int modules = vlc_array_count(&module);
> + while(modules--)
> + demux_Delete(vlc_array_item_at_index(&module, modules));
> + vlc_array_clear(&module);
> +
> + /* then destroy all names and config which weren't destroyed by
> + * sout_StreamDelete */
> + while(i--)
> + {
> + free(vlc_array_item_at_index(&name, i));
> + }
> + vlc_array_clear(&name);
> +
> + return NULL;
> +}
> diff --git a/src/input/demux.h b/src/input/demux.h
> index f841f68..24be9b2 100644
> --- a/src/input/demux.h
> +++ b/src/input/demux.h
> @@ -39,4 +39,7 @@ demux_t *demux_NewAdvanced( vlc_object_t *p_obj,
> input_thread_t *p_parent_input,
> demux_t *input_DemuxNew( vlc_object_t *, const char *access, const
> char *demux,
> const char *path, es_out_t *out, bool
> quick,
> input_thread_t * );
> +
> +demux_t *demux_FilterChainNew( demux_t *p_demux, const char
> *psz_name );
> +
> #endif
> diff --git a/src/input/input.c b/src/input/input.c
> index 5af8256..2169ede 100644
> --- a/src/input/input.c
> +++ b/src/input/input.c
> @@ -2334,6 +2334,15 @@ static input_source_t *InputSourceNew(
> input_thread_t *p_input,
> return NULL;
> }
>
> + char *psz_demux_chain = var_GetNonEmptyString(p_input,
> "demux-filter");
> + /* add the chain of demux filters */
> + demux_t *p_filtered_demux = demux_FilterChainNew( in->p_demux,
> psz_demux_chain );
> + if ( p_filtered_demux != NULL )
> + in->p_demux = p_filtered_demux;
> + else if ( psz_demux_chain != NULL )
> + msg_Dbg(p_input, "Failed to create demux filter %s",
> psz_demux_chain);
> + free( psz_demux_chain );
> +
> /* Get infos from (access_)demux */
> bool b_can_seek;
> if( demux_Control( in->p_demux, DEMUX_CAN_SEEK, &b_can_seek ) )
> diff --git a/src/input/var.c b/src/input/var.c
> index 6534603..437c614 100644
> --- a/src/input/var.c
> +++ b/src/input/var.c
> @@ -513,6 +513,7 @@ void input_ConfigVarInit ( input_thread_t
> *p_input )
> /* */
> var_Create( p_input, "access", VLC_VAR_STRING |
> VLC_VAR_DOINHERIT );
> var_Create( p_input, "demux", VLC_VAR_STRING | VLC_VAR_DOINHERIT
> );
> + var_Create( p_input, "demux-filter", VLC_VAR_STRING |
> VLC_VAR_DOINHERIT );
> var_Create( p_input, "stream-filter", VLC_VAR_STRING |
> VLC_VAR_DOINHERIT );
>
> /* Meta */
> diff --git a/src/libvlc-module.c b/src/libvlc-module.c
> index 74fc7e5..5e7be1d 100644
> --- a/src/libvlc-module.c
> +++ b/src/libvlc-module.c
> @@ -980,6 +980,10 @@ static const char *const ppsz_prefres[] = {
> #define STREAM_FILTER_LONGTEXT N_( \
> "Stream filters are used to modify the stream that is being
> read. " )
>
> +#define DEMUX_FILTER_TEXT N_("Demux filter module")
> +#define DEMUX_FILTER_LONGTEXT N_( \
> + "Demux filters are used to modify/control the stream that is
> being read. " )
> +
> #define DEMUX_TEXT N_("Demux module")
> #define DEMUX_LONGTEXT N_( \
> "Demultiplexers are used to separate the \"elementary\" streams
> " \
> @@ -1868,6 +1872,7 @@ vlc_module_begin ()
> add_module_list( "stream-filter", "stream_filter", NULL,
> STREAM_FILTER_TEXT, STREAM_FILTER_LONGTEXT,
> false )
>
> + add_string( "demux-filter", NULL, DEMUX_FILTER_TEXT,
> DEMUX_FILTER_LONGTEXT, true )
>
> /* Stream output options */
> set_category( CAT_SOUT )
> diff --git a/src/playlist/engine.c b/src/playlist/engine.c
> index 9f3abf0..1ff64c7 100644
> --- a/src/playlist/engine.c
> +++ b/src/playlist/engine.c
> @@ -472,6 +472,7 @@ static void VariablesInit( playlist_t *p_playlist
> )
>
> /* sout variables */
> var_Create( p_playlist, "sout", VLC_VAR_STRING |
> VLC_VAR_DOINHERIT );
> + var_Create( p_playlist, "demux-filter", VLC_VAR_STRING |
> VLC_VAR_DOINHERIT );
>
> /* */
> var_Create( p_playlist, "album-art", VLC_VAR_INTEGER |
> VLC_VAR_DOINHERIT );
--
Rémi Denis-Courmont
http://www.remlab.net/
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