RTP depacketization of Theora

Patch by Josh Allmann (joshua allmann gmail com)

Originally committed as revision 22636 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 387 insertions, 0 deletions

diff --git a/libavformat/rtpdec_theora.c b/libavformat/rtpdec_theora.c
new file mode 100644
index 0000000000..b87a6f7994
--- /dev/null
+++ b/libavformat/rtpdec_theora.c
@@ -0,0 +1,387 @@
+/*
+ * RTP Theora Protocol
+ * Copyright (c) 2010 Josh Allmann
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavformat/rtpdec_theora.c
+ * @brief Theora / RTP Code
+ * @author Josh Allmann <joshua.allmann@gmail.com>
+ */
+
+#include "libavutil/avstring.h"
+#include "libavutil/base64.h"
+#include "libavcodec/bytestream.h"
+
+#include <assert.h>
+
+#include "rtpdec.h"
+#include "rtpdec_theora.h"
+
+/**
+ * RTP/Theora specific private data.
+ */
+struct PayloadContext {
+    unsigned ident;             ///< 24-bit stream configuration identifier
+    uint32_t timestamp;
+    ByteIOContext* fragment;    ///< buffer for split payloads
+};
+
+static PayloadContext *theora_new_context(void)
+{
+    return av_mallocz(sizeof(PayloadContext));
+}
+
+static inline void free_fragment_if_needed(PayloadContext * data)
+{
+    if (data->fragment) {
+        uint8_t* p;
+        url_close_dyn_buf(data->fragment, &p);
+        av_free(p);
+        data->fragment = NULL;
+    }
+}
+
+static void theora_free_context(PayloadContext * data)
+{
+    free_fragment_if_needed(data);
+    av_free(data);
+}
+
+static int theora_handle_packet(AVFormatContext * ctx,
+                                PayloadContext * data,
+                                AVStream * st,
+                                AVPacket * pkt,
+                                uint32_t * timestamp,
+                                const uint8_t * buf, int len, int flags)
+{
+
+    int ident, fragmented, tdt, num_pkts, pkt_len;
+
+    if (len < 6) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
+        return AVERROR_INVALIDDATA;
+    }
+
+    // read theora rtp headers
+    ident       = AV_RB24(buf);
+    fragmented  = buf[3] >> 6;
+    tdt         = (buf[3] >> 4) & 3;
+    num_pkts    = buf[3] & 7;
+    pkt_len     = AV_RB16(buf + 4);
+
+    if (pkt_len > len - 6) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Invalid packet length %d in %d byte packet\n", pkt_len,
+               len);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (ident != data->ident) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Unimplemented Theora SDP configuration change detected\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    if (tdt) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Unimplemented RTP Theora packet settings (%d,%d,%d)\n",
+               fragmented, tdt, num_pkts);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    buf += 6; // move past header bits
+    len -= 6;
+
+    if (fragmented == 0) {
+        // whole frame(s)
+        int i, data_len, write_len;
+        buf -= 2;
+        len += 2;
+
+        // fast first pass to calculate total length
+        for (i = 0, data_len = 0;  (i < num_pkts) && (len >= 2);  i++) {
+            int off   = data_len + (i << 1);
+            pkt_len   = AV_RB16(buf + off);
+            data_len += pkt_len;
+            len      -= pkt_len + 2;
+        }
+
+        if (len < 0 || i < num_pkts) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Bad packet: %d bytes left at frame %d of %d\n",
+                   len, i, num_pkts);
+            return AVERROR_INVALIDDATA;
+        }
+
+        if (av_new_packet(pkt, data_len)) {
+            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+            return AVERROR_NOMEM;
+        }
+        pkt->stream_index = st->index;
+
+        // concatenate frames
+        for (i = 0, write_len = 0; write_len < data_len; i++) {
+            pkt_len = AV_RB16(buf);
+            buf += 2;
+            memcpy(pkt->data + write_len, buf, pkt_len);
+            write_len += pkt_len;
+            buf += pkt_len;
+        }
+        assert(write_len == data_len);
+
+        return 0;
+
+    } else if (fragmented == 1) {
+        // start of theora data fragment
+        int res;
+
+        // end packet has been lost somewhere, so drop buffered data
+        free_fragment_if_needed(data);
+
+        if((res = url_open_dyn_buf(&data->fragment)) < 0)
+            return res;
+
+        put_buffer(data->fragment, buf, pkt_len);
+        data->timestamp = *timestamp;
+
+    } else {
+        assert(fragmented < 4);
+        if (data->timestamp != *timestamp) {
+            // skip if fragmented timestamp is incorrect;
+            // a start packet has been lost somewhere
+            free_fragment_if_needed(data);
+            av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        // copy data to fragment buffer
+        put_buffer(data->fragment, buf, pkt_len);
+
+        if (fragmented == 3) {
+            // end of theora data packet
+            uint8_t* theora_data;
+            int frame_size = url_close_dyn_buf(data->fragment, &theora_data);
+
+            if (frame_size < 0) {
+                av_log(ctx, AV_LOG_ERROR,
+                       "Error occurred when getting fragment buffer.");
+                return frame_size;
+            }
+
+            if (av_new_packet(pkt, frame_size)) {
+                av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+                return AVERROR_NOMEM;
+            }
+
+            memcpy(pkt->data, theora_data, frame_size);
+            pkt->stream_index = st->index;
+
+            av_free(theora_data);
+            data->fragment = NULL;
+
+            return 0;
+        }
+    }
+
+   return AVERROR(EAGAIN);
+}
+
+/**
+ * Length encoding described in RFC5215 section 3.1.1.
+ */
+static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
+{
+    int n = 0;
+    for (; *buf < buf_end; ++*buf) {
+        n <<= 7;
+        n += **buf & 0x7f;
+        if (!(**buf & 0x80)) {
+            ++*buf;
+            return n;
+        }
+    }
+    return 0;
+}
+
+/**
+ * Based off parse_packed_headers in Vorbis RTP
+ */
+static unsigned int
+parse_packed_headers(const uint8_t * packed_headers,
+                     const uint8_t * packed_headers_end,
+                     AVCodecContext * codec, PayloadContext * theora_data)
+{
+
+    unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
+    uint8_t *ptr;
+
+    if (packed_headers_end - packed_headers < 9) {
+        av_log(codec, AV_LOG_ERROR,
+               "Invalid %d byte packed header.",
+               packed_headers_end - packed_headers);
+        return AVERROR_INVALIDDATA;
+    }
+
+    num_packed         = bytestream_get_be32(&packed_headers);
+    theora_data->ident = bytestream_get_be24(&packed_headers);
+    length             = bytestream_get_be16(&packed_headers);
+    num_headers        = get_base128(&packed_headers, packed_headers_end);
+    length1            = get_base128(&packed_headers, packed_headers_end);
+    length2            = get_base128(&packed_headers, packed_headers_end);
+
+    if (num_packed != 1 || num_headers > 3) {
+        av_log(codec, AV_LOG_ERROR,
+               "Unimplemented number of headers: %d packed headers, %d headers\n",
+               num_packed, num_headers);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    if (packed_headers_end - packed_headers != length ||
+        length1 > length || length2 > length - length1) {
+        av_log(codec, AV_LOG_ERROR,
+               "Bad packed header lengths (%d,%d,%d,%d)\n", length1,
+               length2, packed_headers_end - packed_headers, length);
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* allocate extra space:
+     * -- length/255 +2 for xiphlacing
+     * -- one for the '2' marker
+     * -- FF_INPUT_BUFFER_PADDING_SIZE required */
+    extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
+
+    ptr = codec->extradata = av_malloc(extradata_alloc);
+    if (!ptr) {
+        av_log(codec, AV_LOG_ERROR, "Out of memory\n");
+        return AVERROR_NOMEM;
+    }
+    *ptr++ = 2;
+    ptr += av_xiphlacing(ptr, length1);
+    ptr += av_xiphlacing(ptr, length2);
+    memcpy(ptr, packed_headers, length);
+    ptr += length;
+    codec->extradata_size = ptr - codec->extradata;
+    // clear out remaining parts of the buffer
+    memset(ptr, 0, extradata_alloc - codec->extradata_size);
+
+    return 0;
+}
+
+static int theora_parse_fmtp_pair(AVCodecContext * codec,
+                                  PayloadContext *theora_data,
+                                  char *attr, char *value)
+{
+    int result = 0;
+
+    if (!strcmp(attr, "sampling")) {
+        return AVERROR_PATCHWELCOME;
+    } else if (!strcmp(attr, "width")) {
+        /* This is an integer between 1 and 1048561
+         * and MUST be in multiples of 16. */
+        codec->width = atoi(value);
+        return 0;
+    } else if (!strcmp(attr, "height")) {
+        /* This is an integer between 1 and 1048561
+         * and MUST be in multiples of 16. */
+        codec->height = atoi(value);
+        return 0;
+    } else if (!strcmp(attr, "delivery-method")) {
+        /* Possible values are: inline, in_band, out_band/specific_name. */
+        return AVERROR_PATCHWELCOME;
+    } else if (!strcmp(attr, "configuration-uri")) {
+        /* NOTE: configuration-uri is supported only under 2 conditions:
+         *--after the delivery-method tag
+         * --with a delivery-method value of out_band */
+        return AVERROR_PATCHWELCOME;
+    } else if (!strcmp(attr, "configuration")) {
+        /* NOTE: configuration is supported only AFTER the delivery-method tag
+         * The configuration value is a base64 encoded packed header */
+        uint8_t *decoded_packet = NULL;
+        int packet_size;
+        size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
+
+        if (decoded_alloc <= INT_MAX) {
+            decoded_packet = av_malloc(decoded_alloc);
+            if (decoded_packet) {
+                packet_size =
+                    av_base64_decode(decoded_packet, value, decoded_alloc);
+
+                result = parse_packed_headers
+                    (decoded_packet, decoded_packet + packet_size, codec,
+                    theora_data);
+            } else {
+                av_log(codec, AV_LOG_ERROR,
+                       "Out of memory while decoding SDP configuration.\n");
+                result = AVERROR_NOMEM;
+            }
+        } else {
+            av_log(codec, AV_LOG_ERROR, "Packet too large\n");
+            result = AVERROR_INVALIDDATA;
+        }
+        av_free(decoded_packet);
+    }
+    return result;
+}
+
+static int theora_parse_sdp_line(AVFormatContext *s, int st_index,
+                                 PayloadContext *data, const char *line)
+{
+    const char *p;
+    char *value;
+    char attr[25];
+    int value_size = strlen(line), attr_size = sizeof(attr), res = 0;
+    AVCodecContext* codec = s->streams[st_index]->codec;
+
+    assert(codec->id == CODEC_ID_THEORA);
+    assert(data);
+
+    if (!(value = av_malloc(value_size))) {
+        av_log(codec, AV_LOG_ERROR, "Out of memory\n");
+        return AVERROR_NOMEM;
+    }
+
+    if (av_strstart(line, "fmtp:", &p)) {
+        // remove protocol identifier
+        while (*p && *p == ' ') p++; // strip spaces
+        while (*p && *p != ' ') p++; // eat protocol identifier
+        while (*p && *p == ' ') p++; // strip trailing spaces
+
+        while (ff_rtsp_next_attr_and_value(&p,
+                                           attr, attr_size,
+                                           value, value_size)) {
+            res = theora_parse_fmtp_pair(codec, data, attr, value);
+            if (res < 0 && res != AVERROR_PATCHWELCOME)
+                return res;
+        }
+    }
+
+    av_free(value);
+    return 0;
+}
+
+RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
+    .enc_name         = "theora",
+    .codec_type       = CODEC_TYPE_VIDEO,
+    .codec_id         = CODEC_ID_THEORA,
+    .parse_sdp_a_line = theora_parse_sdp_line,
+    .open             = theora_new_context,
+    .close            = theora_free_context,
+    .parse_packet     = theora_handle_packet
+};