img2: stop using CODEC_ID_RAWVIDEO to trigger processing of independant y/u/v image files

This is requireed, as img2 will be modified soon to support .raw image file sequences.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/muxers.texi

@@ -141,6 +141,12 @@ Note also that the pattern must not necessarily contain "%d" or
 ffmpeg -i in.avi -f image2 -vframes 1 img.jpeg
 @end example
 
+The image muxer supports the .Y.U.V image file format. This format is
+special in that that each image frame consists of three files, for
+each of the YUV420P components. To read or write this image file format,
+specify the name of the '.Y' file. The muxer will automatically open the
+'.U' and '.V' files as required.
+
 @section mpegts
 
 MPEG transport stream muxer.

libavformat/img2.c

@@ -32,6 +32,7 @@ typedef struct {
     int img_number;
     int img_count;
     int is_pipe;
+    int split_planes;  /**< use independent file for each Y, U, V plane */
     char path[1024];
 } VideoData;
 
@@ -241,6 +242,8 @@ static int read_header(AVFormatContext *s1, AVFormatParameters *ap)
         st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
         st->codec->codec_id = s1->audio_codec_id;
     }else{
+        const char *str= strrchr(s->path, '.');
+        s->split_planes = str && !strcasecmp(str + 1, "y");
         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
         st->codec->codec_id = av_str2id(img_tags, s->path);
     }
@@ -278,7 +281,7 @@ static int read_packet(AVFormatContext *s1, AVPacket *pkt)
             }
             size[i]= avio_size(f[i]);
 
-            if(codec->codec_id != CODEC_ID_RAWVIDEO)
+            if(!s->split_planes)
                 break;
             filename[ strlen(filename) - 1 ]= 'U' + i;
         }
@@ -324,6 +327,7 @@ static int read_packet(AVFormatContext *s1, AVPacket *pkt)
 static int write_header(AVFormatContext *s)
 {
     VideoData *img = s->priv_data;
+    const char *str;
 
     img->img_number = 1;
     av_strlcpy(img->path, s->filename, sizeof(img->path));
@@ -334,6 +338,8 @@ static int write_header(AVFormatContext *s)
     else
         img->is_pipe = 1;
 
+    str = strrchr(img->path, '.');
+    img->split_planes = str && !strcasecmp(str + 1, "y");
     return 0;
 }
 
@@ -359,7 +365,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
                 return AVERROR(EIO);
             }
 
-            if(codec->codec_id != CODEC_ID_RAWVIDEO)
+            if(!img->split_planes)
                 break;
             filename[ strlen(filename) - 1 ]= 'U' + i;
         }
@@ -367,7 +373,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
         pb[0] = s->pb;
     }
 
-    if(codec->codec_id == CODEC_ID_RAWVIDEO){
+    if(img->split_planes){
         int ysize = codec->width * codec->height;
         avio_write(pb[0], pkt->data        , ysize);
         avio_write(pb[1], pkt->data + ysize, (pkt->size - ysize)/2);