[vlc-devel] [PATCH] [RFC] add demux filters that are similar in API to regular demuxers
Steve Lhomme
robux4 at gmail.com
Mon Jun 6 11:24:24 CEST 2016
On Mon, Jun 6, 2016 at 11:11 AM, Steve Lhomme <robux4 at gmail.com> wrote:
> On Sun, Jun 5, 2016 at 2:15 PM, Rémi Denis-Courmont <remi at remlab.net> wrote:
>> 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.
>
> For now when a demuxer changes the info values, it calls the previous
> demux in line to inform it.
> I guess with the demux_InfoXXX() calls they can be chained with a
> callback so that we always use the top demuxer and the lower demuxer
> doesn't need to know what's before.
>
>>> + 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.
>
> The problem is that in some parts of the code we check if the demuxer
> has a pf_demux function.
>
> http://git.videolan.org/?p=vlc.git;a=blob;f=include/vlc_demux.h;h=f4baeea8a5e97c26d956f4ea34d52051620cf788;hb=HEAD#l301
> http://git.videolan.org/?p=vlc.git;a=blob;f=src/input/input.c;h=d4acfda036fb6c1c196439f2feea4d3c9a539739;hb=HEAD#l706
> http://git.videolan.org/?p=vlc.git;a=blob;f=src/input/input.c;h=d4acfda036fb6c1c196439f2feea4d3c9a539739;hb=HEAD#l2355
>
> I do not understand how a demuxer or an access demuxer can not have
> this callback. So for now I copy the pf_demux from the lower demuxer
> in the demux filters so it's also seen at the top of the demuxer
> chain.
It seems only dvdnav and dvdread are in this case.
>>> };
>>>
>>> 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.
>
> I'll try to chain the calls and get rid of p_prev.
>
>>>
>>> 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/
>> _______________________________________________
>> vlc-devel mailing list
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