rtp: Packetization of JPEG (RFC 2435)

1 files changed, 138 insertions, 0 deletions

diff --git a/libavformat/rtpenc_jpeg.c b/libavformat/rtpenc_jpeg.c
new file mode 100644
index 0000000000..53a5bd2238
--- /dev/null
+++ b/libavformat/rtpenc_jpeg.c
@@ -0,0 +1,138 @@
+/*
+ * RTP JPEG-compressed video Packetizer, RFC 2435
+ * Copyright (c) 2012 Samuel Pitoiset
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavcodec/bytestream.h"
+#include "libavcodec/mjpeg.h"
+#include "libavutil/intreadwrite.h"
+#include "rtpenc.h"
+
+void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
+{
+    RTPMuxContext *s = s1->priv_data;
+    const uint8_t *qtables = NULL;
+    int nb_qtables = 0;
+    uint8_t type = 1; /* default pixel format is PIX_FMT_YUVJ420P */
+    uint8_t w, h;
+    uint8_t *p;
+    int off = 0; /* fragment offset of the current JPEG frame */
+    int len;
+    int i;
+
+    s->buf_ptr   = s->buf;
+    s->timestamp = s->cur_timestamp;
+
+    /* convert video pixel dimensions from pixels to blocks */
+    w = s1->streams[0]->codec->width  >> 3;
+    h = s1->streams[0]->codec->height >> 3;
+
+    /* check if pixel format is not the normal 420 case */
+    if (s1->streams[0]->codec->pix_fmt == PIX_FMT_YUVJ422P) {
+        type = 0;
+    } else if (s1->streams[0]->codec->pix_fmt == PIX_FMT_YUVJ420P) {
+        type = 1;
+    } else {
+        av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
+        return;
+    }
+
+    /* preparse the header for getting some infos */
+    for (i = 0; i < size; i++) {
+        if (buf[i] != 0xff)
+            continue;
+
+        if (buf[i + 1] == DQT) {
+            if (buf[i + 4])
+                av_log(s1, AV_LOG_WARNING,
+                       "Only 8-bit precision is supported.\n");
+
+            /* a quantization table is 64 bytes long */
+            nb_qtables = AV_RB16(&buf[i + 2]) / 65;
+            if (i + 4 + nb_qtables * 65 > size) {
+                av_log(s1, AV_LOG_ERROR, "Too short JPEG header. Aborted!\n");
+                return;
+            }
+
+            qtables = &buf[i + 4];
+        } else if (buf[i + 1] == SOF0) {
+            if (buf[i + 14] != 17 || buf[i + 17] != 17) {
+                av_log(s1, AV_LOG_ERROR,
+                       "Only 1x1 chroma blocks are supported. Aborted!\n");
+                return;
+            }
+        } else if (buf[i + 1] == SOS) {
+            /* SOS is last marker in the header */
+            i += AV_RB16(&buf[i + 2]) + 2;
+            break;
+        }
+    }
+
+    /* skip JPEG header */
+    buf  += i;
+    size -= i;
+
+    for (i = size - 2; i >= 0; i--) {
+        if (buf[i] == 0xff && buf[i + 1] == EOI) {
+            /* Remove the EOI marker */
+            size = i;
+            break;
+        }
+    }
+
+    p = s->buf_ptr;
+    while (size > 0) {
+        int hdr_size = 8;
+
+        if (off == 0 && nb_qtables)
+            hdr_size += 4 + 64 * nb_qtables;
+
+        /* payload max in one packet */
+        len = FFMIN(size, s->max_payload_size - hdr_size);
+
+        /* set main header */
+        bytestream_put_byte(&p, 0);
+        bytestream_put_be24(&p, off);
+        bytestream_put_byte(&p, type);
+        bytestream_put_byte(&p, 255);
+        bytestream_put_byte(&p, w);
+        bytestream_put_byte(&p, h);
+
+        if (off == 0 && nb_qtables) {
+            /* set quantization tables header */
+            bytestream_put_byte(&p, 0);
+            bytestream_put_byte(&p, 0);
+            bytestream_put_be16(&p, 64 * nb_qtables);
+
+            for (i = 0; i < nb_qtables; i++)
+                bytestream_put_buffer(&p, &qtables[65 * i + 1], 64);
+        }
+
+        /* copy payload data */
+        memcpy(p, buf, len);
+
+        /* marker bit is last packet in frame */
+        ff_rtp_send_data(s1, s->buf, len + hdr_size, size == len);
+
+        buf  += len;
+        size -= len;
+        off  += len;
+        p     = s->buf;
+    }
+}