[FFmpeg-devel] [PATCH 1/3] Allow output formats without any streams.

[Anton Khirnov]

Required for future metadata format.
---
 ffmpeg.c               |    2 +-
 libavformat/avformat.h |    1 +
 libavformat/utils.c    |    4 ++--
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/ffmpeg.c b/ffmpeg.c
index 71e5d3b..9491981 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1990,7 +1990,7 @@ static int transcode(AVFormatContext **output_files,
     nb_ostreams = 0;
     for(i=0;i<nb_output_files;i++) {
         os = output_files[i];
-        if (!os->nb_streams) {
+        if (!os->nb_streams && !(os->oformat->flags & AVFMT_NOSTREAMS)) {
             dump_format(output_files[i], i, output_files[i]->filename, 1);
             fprintf(stderr, "Output file #%d does not contain any stream\n", i);
             ret = AVERROR(EINVAL);
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 3079b38..1820ec9 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -323,6 +323,7 @@ typedef struct AVFormatParameters {
 #define AVFMT_TS_DISCONT    0x0200 /**< Format allows timestamp discontinuities. */
 #define AVFMT_VARIABLE_FPS  0x0400 /**< Format allows variable fps. */
 #define AVFMT_NODIMENSIONS  0x0800 /**< Format does not need width/height */
+#define AVFMT_NOSTREAMS     0x1000 /**< Format does not require any streams */
 
 typedef struct AVOutputFormat {
     const char *name;
diff --git a/libavformat/utils.c b/libavformat/utils.c
index c8e6d66..7138f73 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2708,7 +2708,7 @@ int av_write_header(AVFormatContext *s)
     AVStream *st;
 
     // some sanity checks
-    if (s->nb_streams == 0) {
+    if (s->nb_streams == 0 && !(s->oformat->flags & AVFMT_NOSTREAMS)) {
         av_log(s, AV_LOG_ERROR, "no streams\n");
         return AVERROR(EINVAL);
     }
@@ -2776,7 +2776,7 @@ int av_write_header(AVFormatContext *s)
 #endif
 
     /* set muxer identification string */
-    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
+    if (s->nb_streams && !(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
         av_metadata_set2(&s->metadata, "encoder", LIBAVFORMAT_IDENT, 0);
     }
 
-- 
1.7.2.3