hwaccel: Call ->get_format again if hwaccel init fails

This allows the application to fall back on another hwaccel or,
more likely, software decoding.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index bc5f1346f2..dfbab9b60f 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1294,6 +1294,10 @@ typedef struct AVCodecContext {
      * @param fmt is the list of formats which are supported by the codec,
      * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
      * The first is always the native one.
+     * @note The callback may be called again immediately if initialization for
+     * the selected (hardware-accelerated) pixel format failed.
+     * @warning Behavior is undefined if the callback returns a value not
+     * in the fmt list of formats.
      * @return the chosen format
      * - encoding: unused
      * - decoding: Set by user, if not set the native format will be chosen.