RoQ encoder: support different integer framerates

Even though the most common framerate for RoQ is 30fps,
the format supports other framerates too.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 28 insertions, 2 deletions

diff --git a/libavformat/idroqenc.c b/libavformat/idroqenc.c
index 50c428046b..28a3aba9d4 100644
--- a/libavformat/idroqenc.c
+++ b/libavformat/idroqenc.c
@@ -25,9 +25,35 @@
 
 static int roq_write_header(struct AVFormatContext *s)
 {
-    static const uint8_t header[] = {
-        0x84, 0x10, 0xFF, 0xFF, 0xFF, 0xFF, 0x1E, 0x00
+    uint8_t header[] = {
+        0x84, 0x10, 0xFF, 0xFF, 0xFF, 0xFF, /* fps: */ 0x1E, 0x00
     };
+    int n;
+    AVCodecContext *avctx;
+
+// set the actual fps
+    for(n=0;n<s->nb_streams;n++) {
+        if ((avctx=s->streams[n]->codec)->codec_type == AVMEDIA_TYPE_VIDEO) {
+            unsigned int fps;
+
+            if (avctx->time_base.num != 1) {
+                av_log(avctx, AV_LOG_ERROR, "Frame rate must be integer\n");
+                return AVERROR(EINVAL);
+            }
+
+            if ((fps=avctx->time_base.den) > 255) {
+                av_log(avctx, AV_LOG_ERROR, "Frame rate may not exceed 255fps\n");
+                return AVERROR(EINVAL);
+            }
+
+            if (fps != 30) {
+                av_log(avctx, AV_LOG_WARNING, "For vintage compatibility fps must be 30\n");
+            }
+
+            header[6] = fps;
+            break;
+        }
+    }
 
     avio_write(s->pb, header, 8);
     avio_flush(s->pb);