avformat: Deprecate AVFMT_FLAG_PRIV_OPT, remove av_demuxer_open on bump

This flag was added in 492026209b
in conjunction with av_demuxer_open() to allow to pass private
options to demuxers. It worked as follows: av_open_input_stream()
(the predecessor of avformat_open_input()) would not call the
read_header function if this flag is set. Instead the user could set
private options of the demuxer via the format's private class after
avformat_open_input() and then call av_demuxer_open() which called
the format's read_header function.

This approach was abandoned in e37f161e66
and av_demuxer_open() deprecated; instead the AVDictionary based way of
passing private options to the demuxer was choosen. Yet
AVFMT_FLAG_PRIV_OPT has never been deprecated and av_demuxer_open()
never removed. This commit implements the deprecation of the flag and
schedules av_demuxer_open for removal on the next major bump.
Given that av_demuxer_open() has been deprecated in 2012 and that this
flag is useless without it, the flag will be ignored after the next
major version bump.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

doc/APIchanges

@@ -15,6 +15,10 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2021-03-03 - xxxxxxxxxx - lavf 58.70.100 - avformat.h
+  Deprecate AVFMT_FLAG_PRIV_OPT. It will do nothing
+  as soon as av_demuxer_open() is removed.
+
 2021-02-27 - xxxxxxxxxx - lavc 58.126.100 - avcodec.h
   Deprecated avcodec_get_frame_class().
 

libavformat/avformat.h

@@ -1379,7 +1379,9 @@ typedef struct AVFormatContext {
 #define AVFMT_FLAG_MP4A_LATM    0x8000 ///< Deprecated, does nothing.
 #endif
 #define AVFMT_FLAG_SORT_DTS    0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
-#define AVFMT_FLAG_PRIV_OPT    0x20000 ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
+#if FF_API_LAVF_PRIV_OPT
+#define AVFMT_FLAG_PRIV_OPT    0x20000 ///< Enable use of private options by delaying codec open (deprecated, will do nothing once av_demuxer_open() is removed)
+#endif
 #if FF_API_LAVF_KEEPSIDE_FLAG
 #define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Deprecated, does nothing.
 #endif
@@ -2210,8 +2212,13 @@ int av_probe_input_buffer(AVIOContext *pb, ff_const59 AVInputFormat **fmt,
  */
 int avformat_open_input(AVFormatContext **ps, const char *url, ff_const59 AVInputFormat *fmt, AVDictionary **options);
 
+#if FF_API_DEMUXER_OPEN
+/**
+ * @deprecated Use an AVDictionary to pass options to a demuxer.
+ */
 attribute_deprecated
 int av_demuxer_open(AVFormatContext *ic);
+#endif
 
 /**
  * Read packets of a media file to get stream information. This

libavformat/utils.c

@@ -392,6 +392,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
 /************************************************************/
 /* input media file */
 
+#if FF_API_DEMUXER_OPEN
 int av_demuxer_open(AVFormatContext *ic) {
     int err;
 
@@ -411,7 +412,7 @@ int av_demuxer_open(AVFormatContext *ic) {
 
     return 0;
 }
-
+#endif
 /* Open input file and probe the format if necessary. */
 static int init_input(AVFormatContext *s, const char *filename,
                       AVDictionary **options)
@@ -594,8 +595,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
     if (s->pb)
         ff_id3v2_read_dict(s->pb, &s->internal->id3v2_meta, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);
 
-
+#if FF_API_DEMUXER_OPEN
     if (!(s->flags&AVFMT_FLAG_PRIV_OPT) && s->iformat->read_header)
+#else
+    if (s->iformat->read_header)
+#endif
         if ((ret = s->iformat->read_header(s)) < 0)
             goto fail;
 
@@ -624,7 +628,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
     if ((ret = avformat_queue_attached_pictures(s)) < 0)
         goto close;
 
+#if FF_API_DEMUXER_OPEN
     if (!(s->flags&AVFMT_FLAG_PRIV_OPT) && s->pb && !s->internal->data_offset)
+#else
+    if (s->pb && !s->internal->data_offset)
+#endif
         s->internal->data_offset = avio_tell(s->pb);
 
     s->internal->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
-#define LIBAVFORMAT_VERSION_MINOR  69
+#define LIBAVFORMAT_VERSION_MINOR  70
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
@@ -106,6 +106,12 @@
 #ifndef FF_API_AVIOFORMAT
 #define FF_API_AVIOFORMAT               (LIBAVFORMAT_VERSION_MAJOR < 59)
 #endif
+#ifndef FF_API_DEMUXER_OPEN
+#define FF_API_DEMUXER_OPEN             (LIBAVFORMAT_VERSION_MAJOR < 59)
+#endif
+#ifndef FF_API_LAVF_PRIV_OPT
+#define FF_API_LAVF_PRIV_OPT            (LIBAVFORMAT_VERSION_MAJOR < 60)
+#endif
 
 
 #ifndef FF_API_R_FRAME_RATE