extracted yuv4mpeg from img.c (untested)

Originally committed as revision 1437 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/yuv4mpeg.c

+/*
+ * YUV4MPEG format
+ * Copyright (c) 2001, 2002, 2003 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "avformat.h"
+
+#define Y4M_MAGIC "YUV4MPEG2"
+#define Y4M_FRAME_MAGIC "FRAME"
+#define Y4M_LINE_MAX 256
+
+static int yuv4_write_header(AVFormatContext *s)
+{
+    AVStream *st;
+    int width, height;
+    int raten, rated, aspectn, aspectd, fps, fps1, n;
+    char buf[Y4M_LINE_MAX+1];
+
+    if (s->nb_streams != 1)
+        return -EIO;
+    
+    st = s->streams[0];
+    width = st->codec.width;
+    height = st->codec.height;
+    
+    fps = st->codec.frame_rate;
+    fps1 = (((float)fps / FRAME_RATE_BASE) * 1000);
+   
+   /* Sorry about this messy code, but mpeg2enc is very picky about
+    * the framerates it accepts. */
+    switch(fps1) {
+    case 23976:
+        raten = 24000; /* turn the framerate into a ratio */
+        rated = 1001;
+        break;
+    case 29970:
+        raten = 30000;
+        rated = 1001;
+        break;
+    case 25000:
+        raten = 25;
+        rated = 1;
+        break;
+    case 30000:
+        raten = 30;
+        rated = 1;
+        break;
+    case 24000:
+        raten = 24;
+        rated = 1;
+        break;
+    case 50000:
+        raten = 50;
+        rated = 1;
+        break;
+    case 59940:
+        raten = 60000;
+        rated = 1001;
+        break;
+    case 60000:
+        raten = 60;
+        rated = 1;
+        break;
+    default:
+        raten = fps1; /* this setting should work, but often doesn't */
+        rated = 1000;
+        break;
+    }
+    
+    aspectn = 1;
+    aspectd = 1;	/* ffmpeg always uses a 1:1 aspect ratio */
+
+    /* construct stream header, if this is the first frame */
+    n = snprintf(buf, sizeof(buf), "%s W%d H%d F%d:%d I%s A%d:%d\n",
+                 Y4M_MAGIC,
+                 width,
+                 height,
+                 raten, rated,
+                 "p",			/* ffmpeg seems to only output progressive video */
+                 aspectn, aspectd);
+    if (n < 0) {
+        fprintf(stderr, "Error. YUV4MPEG stream header write failed.\n");
+        return -EIO;
+    } else {
+        put_buffer(&s->pb, buf, strlen(buf));
+    }
+    return 0;
+}
+
+static int yuv4_write_packet(AVFormatContext *s, int stream_index,
+                             UINT8 *buf, int size, int force_pts)
+{
+    AVStream *st = s->streams[stream_index];
+    ByteIOContext *pb = &s->pb;
+    AVPicture *picture;
+    int width, height;
+    int i, m;
+    char buf1[20];
+    UINT8 *ptr, *ptr1, *ptr2;
+
+    picture = (AVPicture *)buf;
+
+    /* construct frame header */
+    m = snprintf(buf1, sizeof(buf1), "%s \n", Y4M_FRAME_MAGIC);
+    put_buffer(pb, buf1, strlen(buf1));
+
+    width = st->codec.width;
+    height = st->codec.height;
+    
+    ptr = picture->data[0];
+    for(i=0;i<height;i++) {
+        put_buffer(pb, ptr, width);
+        ptr += picture->linesize[0];
+    }
+
+    height >>= 1;
+    width >>= 1;
+    ptr1 = picture->data[1];
+    ptr2 = picture->data[2];
+    for(i=0;i<height;i++) {		/* Cb */
+        put_buffer(pb, ptr1, width);
+        ptr1 += picture->linesize[1];
+    }
+    for(i=0;i<height;i++) {	/* Cr */
+        put_buffer(pb, ptr2, width);
+            ptr2 += picture->linesize[2];
+    }
+    put_flush_packet(pb);
+    return 0;
+}
+
+static int yuv4_write_trailer(AVFormatContext *s)
+{
+    return 0;
+}
+
+AVOutputFormat yuv4mpegpipe_oformat = {
+    "yuv4mpegpipe",
+    "YUV4MPEG pipe format",
+    "",
+    "yuv4mpeg",
+    0,
+    CODEC_ID_NONE,
+    CODEC_ID_RAWVIDEO,
+    yuv4_write_header,
+    yuv4_write_packet,
+    yuv4_write_trailer,
+    .flags = AVFMT_RAWPICTURE,
+};
+
+