avformat/avio: Add Metacube support

[ffmpeg] / libavformat / avio.h

diff --git a/libavformat/avio.h b/libavformat/avio.h
index 75912ce6bed97dd2cb9ca503d7103821c1f10db1..bf74f2bbbe45e009314070ec9a6bb3d2cc90055e 100644 (file)
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -236,7 +236,7 @@ typedef struct AVIOContext {
     int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
     int64_t (*seek)(void *opaque, int64_t offset, int whence);
     int64_t pos;            /**< position in the file of the current buffer */
-    int eof_reached;        /**< true if eof reached */
+    int eof_reached;        /**< true if was unable to read due to error or eof */
     int write_flag;         /**< true if open for writing */
     int max_packet_size;
     unsigned long checksum;
@@ -349,6 +349,30 @@ typedef struct AVIOContext {
      * Try to buffer at least this amount of data before flushing it
      */
     int min_packet_size;
+
+    /**
+     * If set, all output will be wrapped in the Metacube format,
+     * for consumption by the Cubemap reflector. This is so that Cubemap
+     * can know what the header is, and where it is possible to start
+     * the stream (ie., from keyframes) without actually parsing and
+     * understanding the mux. Only relevant if write_flag is set.
+     *
+     * When wrapping in Metacube, s->buffer will have room for a 16-byte
+     * Metacube header while writing, which is constructed in avio_flush()
+     * before sending. This header is invisible to the calling code;
+     * e.g., it will not be counted in seeks and similar.
+     */
+    int metacube;
+
+    /**
+     * If the metacube flag is set, we need to know whether we've seen
+     * at least one sync point marker (AVIO_DATA_MARKER_SYNC_POINT),
+     * as many muxes don't send them out at all. If we haven't seen any sync
+     * point markers, we assume that all packets (in particular
+     * AVIO_DATA_MARKER_UNKNOWN) are valid sync start points.
+     * (This may not hold for all codecs in practice.)
+     */
+    int seen_sync_point;
 } AVIOContext;
 
 /**
@@ -566,14 +590,34 @@ static av_always_inline int64_t avio_tell(AVIOContext *s)
 int64_t avio_size(AVIOContext *s);
 
 /**
- * feof() equivalent for AVIOContext.
- * @return non zero if and only if end of file
+ * Similar to feof() but also returns nonzero on read errors.
+ * @return non zero if and only if at end of file or a read error happened when reading.
  */
 int avio_feof(AVIOContext *s);
 
-/** @warning Writes up to 4 KiB per call */
+/**
+ * Writes a formatted string to the context.
+ * @return number of bytes written, < 0 on error.
+ */
 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
 
+/**
+ * Write a NULL terminated array of strings to the context.
+ * Usually you don't need to use this function directly but its macro wrapper,
+ * avio_print.
+ */
+void avio_print_string_array(AVIOContext *s, const char *strings[]);
+
+/**
+ * Write strings (const char *) to the context.
+ * This is a convenience macro around avio_print_string_array and it
+ * automatically creates the string array from the variable argument list.
+ * For simple string concatenations this function is more performant than using
+ * avio_printf since it does not need a temporary buffer.
+ */
+#define avio_print(s, ...) \
+    avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
+
 /**
  * Force flushing of buffered data.
  *
@@ -672,6 +716,12 @@ int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
  */
 #define AVIO_FLAG_NONBLOCK 8
 
+/**
+ * If set, all output will be wrapped in the Metacube format.
+ * See AVIOContext::metacube for more information.
+ */
+#define AVIO_FLAG_METACUBE 16
+
 /**
  * Use direct mode.
  * avio_read and avio_write should if possible be satisfied directly
@@ -787,6 +837,13 @@ int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
  */
 const char *avio_enum_protocols(void **opaque, int output);
 
+/**
+ * Get AVClass by names of available protocols.
+ *
+ * @return A AVClass of input protocol name or NULL
+ */
+const AVClass *avio_protocol_get_class(const char *name);
+
 /**
  * Pause and resume playing - only meaningful if using a network streaming
  * protocol (e.g. MMS).