cmdutils: Add a stream specifier to map usable streams

It drops everything that cannot be used for re-encoding and/or
streamcopy.

1 files changed, 22 insertions, 0 deletions

diff --git a/cmdutils.c b/cmdutils.c
index e01ad24906..af8354aa19 100644
--- a/cmdutils.c
+++ b/cmdutils.c
@@ -1587,6 +1587,28 @@ int check_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
 
         av_freep(&key);
         return ret;
+    } else if (*spec == 'u') {
+        AVCodecContext *avctx = st->codec;
+        int val;
+        switch (avctx->codec_type) {
+        case AVMEDIA_TYPE_AUDIO:
+            val = avctx->sample_rate && avctx->channels;
+            if (avctx->sample_fmt == AV_SAMPLE_FMT_NONE)
+                return 0;
+            break;
+        case AVMEDIA_TYPE_VIDEO:
+            val = avctx->width && avctx->height;
+            if (avctx->pix_fmt == AV_PIX_FMT_NONE)
+                return 0;
+            break;
+        case AVMEDIA_TYPE_UNKNOWN:
+            val = 0;
+            break;
+        default:
+            val = 1;
+            break;
+        }
+        return avctx->codec_id != AV_CODEC_ID_NONE && val != 0;
     } else if (!*spec) /* empty specifier, matches everything */
         return 1;