lavf: add new API for iterating muxers and demuxers

Makefile

@@ -143,7 +143,8 @@ distclean:: clean
 		ffbuild/.config ffbuild/config.* libavutil/avconfig.h \
 		version.h libavutil/ffversion.h libavcodec/codec_names.h \
 		libavcodec/bsf_list.c libavformat/protocol_list.c \
-		libavcodec/codec_list.c libavcodec/parser_list.c
+		libavcodec/codec_list.c libavcodec/parser_list.c \
+		libavformat/muxer_list.c libavformat/demuxer_list.c
 ifeq ($(SRC_LINK),src)
 	$(RM) src
 endif

configure

@@ -3525,8 +3525,6 @@ find_things(){
     sed -n "s/^[^#]*$pattern.*([^,]*, *\([^,]*\)\(,.*\)*).*/\1_$thing/p" "$file"
 }
 
-MUXER_LIST=$(find_things    muxer    _MUX     libavformat/allformats.c)
-DEMUXER_LIST=$(find_things  demuxer  DEMUX    libavformat/allformats.c)
 OUTDEV_LIST=$(find_things   outdev   OUTDEV   libavdevice/alldevices.c)
 INDEV_LIST=$(find_things    indev    _IN      libavdevice/alldevices.c)
 FILTER_LIST=$(find_things   filter   FILTER   libavfilter/allfilters.c)
@@ -3538,6 +3536,8 @@ find_things_extern(){
     sed -n "s/^[^#]*extern.*$pattern *ff_\([^ ]*\)_$thing;/\1_$thing/p" "$file"
 }
 
+MUXER_LIST=$(find_things_extern muxer AVOutputFormat libavformat/allformats.c)
+DEMUXER_LIST=$(find_things_extern demuxer AVInputFormat libavformat/allformats.c)
 ENCODER_LIST=$(find_things_extern encoder AVCodec libavcodec/allcodecs.c)
 DECODER_LIST=$(find_things_extern decoder AVCodec libavcodec/allcodecs.c)
 CODEC_LIST="
@@ -7036,6 +7036,8 @@ print_enabled_components(){
 print_enabled_components libavcodec/codec_list.c AVCodec codec_list $CODEC_LIST
 print_enabled_components libavcodec/parser_list.c AVCodecParser parser_list $PARSER_LIST
 print_enabled_components libavcodec/bsf_list.c AVBitStreamFilter bitstream_filters $BSF_LIST
+print_enabled_components libavformat/demuxer_list.c AVInputFormat demuxer_list $DEMUXER_LIST
+print_enabled_components libavformat/muxer_list.c AVOutputFormat muxer_list $MUXER_LIST
 print_enabled_components libavformat/protocol_list.c URLProtocol url_protocols $PROTOCOL_LIST
 
 # Settings for pkg-config files

doc/APIchanges

@@ -15,7 +15,12 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
-2018-01-xx - xxxxxxx - lavc 58.9.100 - avcodec.h
+2018-xx-xx - xxxxxxx - lavf 58.9.100 - avformat.h
+  Deprecate use of av_register_input_format(), av_register_output_format(),
+  avformat_register_all(), av_iformat_next(), av_oformat_next().
+  Add av_demuxer_iterate(), and av_muxer_iterate().
+
+2018-xx-xx - xxxxxxx - lavc 58.9.100 - avcodec.h
   Deprecate use of avcodec_register(), avcodec_register_all(), and
   av_codec_next(). Add av_codec_iterate().
 

libavformat/.gitignore

 /protocol_list.c
+/muxer_list.c
+/demuxer_list.c

libavformat/avformat.h

@@ -2011,6 +2011,7 @@ const char *avformat_configuration(void);
  */
 const char *avformat_license(void);
 
+#if FF_API_NEXT
 /**
  * Initialize libavformat and register all the muxers, demuxers and
  * protocols. If you do not call this function, then you can select
@@ -2019,10 +2020,14 @@ const char *avformat_license(void);
  * @see av_register_input_format()
  * @see av_register_output_format()
  */
+attribute_deprecated
 void av_register_all(void);
 
+attribute_deprecated
 void av_register_input_format(AVInputFormat *format);
+attribute_deprecated
 void av_register_output_format(AVOutputFormat *format);
+#endif
 
 /**
  * Do global initialization of network libraries. This is optional,
@@ -2046,11 +2051,13 @@ int avformat_network_init(void);
  */
 int avformat_network_deinit(void);
 
+#if FF_API_NEXT
 /**
  * If f is NULL, returns the first registered input format,
  * if f is non-NULL, returns the next registered input format after f
  * or NULL if f is the last one.
  */
+attribute_deprecated
 AVInputFormat  *av_iformat_next(const AVInputFormat  *f);
 
 /**
@@ -2058,7 +2065,31 @@ AVInputFormat  *av_iformat_next(const AVInputFormat  *f);
  * if f is non-NULL, returns the next registered output format after f
  * or NULL if f is the last one.
  */
+attribute_deprecated
 AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
+#endif
+
+/**
+ * Iterate over all registered muxers.
+ *
+ * @param opaque a pointer where libavformat will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered muxer or NULL when the iteration is
+ *         finished
+ */
+const AVOutputFormat *av_muxer_iterate(void **opaque);
+
+/**
+ * Iterate over all registered demuxers.
+ *
+ * @param opaque a pointer where libavformat will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered demuxer or NULL when the iteration is
+ *         finished
+ */
+const AVInputFormat *av_demuxer_iterate(void **opaque);
 
 /**
  * Allocate an AVFormatContext.

libavformat/format.c

@@ -34,65 +34,6 @@
  * @file
  * Format register and lookup
  */
-/** head of registered input format linked list */
-static AVInputFormat *first_iformat = NULL;
-/** head of registered output format linked list */
-static AVOutputFormat *first_oformat = NULL;
-
-static AVInputFormat **last_iformat = &first_iformat;
-static AVOutputFormat **last_oformat = &first_oformat;
-
-AVInputFormat *av_iformat_next(const AVInputFormat *f)
-{
-    if (f)
-        return f->next;
-    else
-        return first_iformat;
-}
-
-AVOutputFormat *av_oformat_next(const AVOutputFormat *f)
-{
-    if (f)
-        return f->next;
-    else
-        return first_oformat;
-}
-
-static AVMutex iformat_register_mutex = AV_MUTEX_INITIALIZER;
-
-void av_register_input_format(AVInputFormat *format)
-{
-    AVInputFormat **p;
-
-    ff_mutex_lock(&iformat_register_mutex);
-    p = last_iformat;
-
-    while (*p)
-        p = &(*p)->next;
-    *p = format;
-    format->next = NULL;
-    last_iformat = &format->next;
-
-    ff_mutex_unlock(&iformat_register_mutex);
-}
-
-static AVMutex oformat_register_mutex = AV_MUTEX_INITIALIZER;
-
-void av_register_output_format(AVOutputFormat *format)
-{
-    AVOutputFormat **p;
-
-    ff_mutex_lock(&oformat_register_mutex);
-    p = last_oformat;
-
-    while (*p)
-        p = &(*p)->next;
-    *p = format;
-    format->next = NULL;
-    last_oformat = &format->next;
-
-    ff_mutex_unlock(&oformat_register_mutex);
-}
 
 int av_match_ext(const char *filename, const char *extensions)
 {
@@ -111,6 +52,7 @@ AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
                                 const char *mime_type)
 {
     AVOutputFormat *fmt = NULL, *fmt_found;
+    void *i = 0;
     int score_max, score;
 
     /* specific test for image sequences */
@@ -124,7 +66,7 @@ AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
     /* Find the proper file type. */
     fmt_found = NULL;
     score_max = 0;
-    while ((fmt = av_oformat_next(fmt))) {
+    while ((fmt = av_muxer_iterate(&i))) {
         score = 0;
         if (fmt->name && short_name && av_match_name(short_name, fmt->name))
             score += 100;
@@ -176,7 +118,8 @@ enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
 AVInputFormat *av_find_input_format(const char *short_name)
 {
     AVInputFormat *fmt = NULL;
-    while ((fmt = av_iformat_next(fmt)))
+    void *i = 0;
+    while ((fmt = av_demuxer_iterate(&i)))
         if (av_match_name(short_name, fmt->name))
             return fmt;
     return NULL;
@@ -188,6 +131,7 @@ AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened,
     AVProbeData lpd = *pd;
     AVInputFormat *fmt1 = NULL, *fmt;
     int score, score_max = 0;
+    void *i = 0;
     const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
     enum nodat {
         NO_ID3,
@@ -213,7 +157,7 @@ AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened,
     }
 
     fmt = NULL;
-    while ((fmt1 = av_iformat_next(fmt1))) {
+    while ((fmt1 = av_demuxer_iterate(&i))) {
         if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
             continue;
         score = 0;

libavformat/version.h

@@ -91,6 +91,9 @@
 #ifndef FF_API_OLD_RTSP_OPTIONS
 #define FF_API_OLD_RTSP_OPTIONS         (LIBAVFORMAT_VERSION_MAJOR < 59)
 #endif
+#ifndef FF_API_NEXT
+#define FF_API_NEXT                     (LIBAVFORMAT_VERSION_MAJOR < 59)
+#endif
 
 
 #ifndef FF_API_R_FRAME_RATE