Add a depacketizer for QDM2

Patch by Josh Allmann, joshua dot allmann at gmail, original code
by Ronald S Bultje.

Originally committed as revision 24236 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 316 insertions, 0 deletions

diff --git a/libavformat/rtpdec_qdm2.c b/libavformat/rtpdec_qdm2.c
new file mode 100644
index 0000000000..9c6b3efc92
--- /dev/null
+++ b/libavformat/rtpdec_qdm2.c
@@ -0,0 +1,316 @@
+/*
+ * QDesign Music 2 (QDM2) payload for RTP
+ * Copyright (c) 2010 Ronald S. Bultje
+ *
+ * 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
+ * @brief RTP support for the QDM2 payload (todo: wiki)
+ * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
+ */
+
+#include <string.h>
+#include "libavutil/intreadwrite.h"
+#include "libavcodec/avcodec.h"
+#include "rtp.h"
+#include "rtpdec.h"
+#include "rtpdec_qdm2.h"
+
+struct PayloadContext {
+    /** values read from the config header, used as packet headers */
+    //@{
+    int block_type;            ///< superblock type, value 2 .. 8
+    int block_size;            ///< from extradata, used as pkt length
+    int subpkts_per_block;     ///< max. nr. of subpackets to add per output buffer
+    //@}
+
+    /** Temporary storage for superblock restoring, per packet ID (0x80 total) */
+    //@{
+    uint16_t len[0x80];        ///< how much the temporary buffer is filled
+    uint8_t  buf[0x80][0x800]; ///< the temporary storage buffer
+
+    unsigned int cache;        ///< number of data packets that we have cached right now
+    unsigned int n_pkts;       ///< number of RTP packets received since last packet output / config
+    uint32_t timestamp;        ///< timestamp of next-to-be-returned packet
+    //@}
+};
+
+/**
+ * Parses configuration (basically the codec-specific extradata) from
+ * a RTP config subpacket (starts with 0xff).
+ *
+ * Layout of the config subpacket (in bytes):
+ * 1: 0xFF          <- config ID
+ * then an array {
+ *     1: size      <- of the current item
+ *     1: item type <- 0 .. 4
+ *     size-2: data <- data depends on the item type
+ * }
+ *
+ * Item 0 implies the end of the config subpacket, and has no data.
+ * Item 1 implies a stream configuration without extradata.
+ * Item 2 max. nr. of subpackets per superblock
+ * Item 3 superblock type for the stream
+ * Item 4 implies a stream configuration with extradata (size >= 0x1c).
+ *
+ * @return <0 on error, otherwise the number of bytes parsed from the
+ *         input buffer.
+ */
+static int qdm2_parse_config(PayloadContext *qdm, AVStream *st,
+                             const uint8_t *buf, const uint8_t *end)
+{
+    const uint8_t *p = buf;
+
+    while (end - p >= 2) {
+        unsigned int item_len = p[0], config_item = p[1];
+
+        if (item_len < 2 || end - p < item_len || config_item > 4)
+            return AVERROR_INVALIDDATA;
+
+        switch (config_item) {
+            case 0: /* end of config block */
+                return p - buf + item_len;
+            case 1: /* stream without extradata */
+                /* FIXME: set default qdm->block_size */
+                break;
+            case 2: /**< subpackets per block */
+                if (item_len < 3)
+                    return AVERROR_INVALIDDATA;
+                qdm->subpkts_per_block = p[2];
+                break;
+            case 3: /* superblock type */
+                if (item_len < 4)
+                    return AVERROR_INVALIDDATA;
+                qdm->block_type = AV_RB16(p + 2);
+                break;
+            case 4: /* stream with extradata */
+                if (item_len < 30)
+                    return AVERROR_INVALIDDATA;
+                av_freep(&st->codec->extradata);
+                st->codec->extradata_size = 26 + item_len;
+                if (!(st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE))) {
+                    st->codec->extradata_size = 0;
+                    return AVERROR(ENOMEM);
+                }
+                AV_WB32(st->codec->extradata, 12);
+                memcpy(st->codec->extradata + 4, "frma", 4);
+                memcpy(st->codec->extradata + 8, "QDM2", 4);
+                AV_WB32(st->codec->extradata + 12, 6 + item_len);
+                memcpy(st->codec->extradata + 16, "QDCA", 4);
+                memcpy(st->codec->extradata + 20, p + 2, item_len - 2);
+                AV_WB32(st->codec->extradata + 18 + item_len, 8);
+                AV_WB32(st->codec->extradata + 22 + item_len, 0);
+
+                qdm->block_size = AV_RB32(p + 26);
+                break;
+        }
+
+        p += item_len;
+    }
+
+    return AVERROR(EAGAIN); /* not enough data */
+}
+
+/**
+ * Parses a single subpacket. We store this subpacket in an intermediate
+ * buffer (position depends on the ID (byte[0]). When called, at least
+ * 4 bytes are available for reading (see qdm2_parse_packet()).
+ *
+ * Layout of a single subpacket (RTP packets commonly contain multiple
+ * such subpackets) - length in bytes:
+ * 1:    ordering ID        <- 0 .. 0x7F
+ * 1:    subpacket type     <- 0 .. 0x7F; value & 0x80 means subpacket length = 2 bytes, else 1 byte
+ * 1/2:  subpacket length   <- length of the data following the flags/length fields
+ * if (subpacket type & 0x7F) == 0x7F
+ *   1:  subpacket type, higher bits
+ * size: subpacket data
+ *
+ * The subpackets come in randomly, and should be encapsulated into 1
+ * or more superblocks (containing qdm->subpkts_per_block subpackets
+ * each) per RTP packet, in order of ascending "ordering ID", see
+ * qdm2_restore_block().
+ *
+ * @return <0 on error, otherwise the number of bytes parsed from the
+ *         input buffer.
+ */
+static int qdm2_parse_subpacket(PayloadContext *qdm, AVStream *st,
+                                const uint8_t *buf, const uint8_t *end)
+{
+    const uint8_t *p = buf;
+    unsigned int id, len, type, to_copy;
+
+    /* parse header so we know the size of the header/data */
+    id       = *p++;
+    type     = *p++;
+    if (type & 0x80) {
+        len   = AV_RB16(p);
+        p    += 2;
+        type &= 0x7F;
+    } else
+        len = *p++;
+
+    if (end - p < len + (type == 0x7F) || id >= 0x80)
+        return AVERROR_INVALIDDATA;
+    if (type == 0x7F)
+        type |= *p++ << 8;
+
+    /* copy data into a temporary buffer */
+    to_copy = FFMIN(len + (p - &buf[1]), 0x800 - qdm->len[id]);
+    memcpy(&qdm->buf[id][qdm->len[id]], buf + 1, to_copy);
+    qdm->len[id] += to_copy;
+
+    return p + len - buf;
+}
+
+/**
+ * Adds a superblock header around a set of subpackets.
+ *
+ * @return <0 on error, else 0.
+ */
+static int qdm2_restore_block(PayloadContext *qdm, AVStream *st, AVPacket *pkt)
+{
+    int to_copy, n, res, include_csum;
+    uint8_t *p, *csum_pos = NULL;
+
+    /* create packet to hold subpkts into a superblock */
+    assert(qdm->cache > 0);
+    for (n = 0; n < 0x80; n++)
+        if (qdm->len[n] > 0)
+            break;
+    assert(n < 0x80);
+
+    if ((res = av_new_packet(pkt, qdm->block_size)) < 0)
+        return res;
+    memset(pkt->data, 0, pkt->size);
+    pkt->stream_index  = st->index;
+    p                  = pkt->data;
+
+    /* superblock header */
+    if (qdm->len[n] > 0xff) {
+        *p++ = qdm->block_type | 0x80;
+        AV_WB16(p, qdm->len[n]);
+        p   += 2;
+    } else {
+        *p++ = qdm->block_type;
+        *p++ = qdm->len[n];
+    }
+    if ((include_csum = (qdm->block_type == 2 || qdm->block_type == 4))) {
+        csum_pos = p;
+        p       += 2;
+    }
+
+    /* subpacket data */
+    to_copy = FFMIN(qdm->len[n], pkt->size - (p - pkt->data));
+    memcpy(p, qdm->buf[n], to_copy);
+    qdm->len[n] = 0;
+
+    /* checksum header */
+    if (include_csum) {
+        unsigned int total = 0;
+        uint8_t *q;
+
+        for (q = pkt->data; q < &pkt->data[qdm->block_size]; q++)
+            total += *q;
+        AV_WB16(csum_pos, (uint16_t) total);
+    }
+
+    return 0;
+}
+
+/** return 0 on packet, no more left, 1 on packet, -1 on partial packet... */
+static int qdm2_parse_packet(AVFormatContext *s, PayloadContext *qdm,
+                             AVStream *st, AVPacket *pkt,
+                             uint32_t *timestamp,
+                             const uint8_t *buf, int len, int flags)
+{
+    int res = AVERROR_INVALIDDATA, n;
+    const uint8_t *end = buf + len, *p = buf;
+
+    if (len > 0) {
+        if (len < 2)
+            return AVERROR_INVALIDDATA;
+
+        /* configuration block */
+        if (*p == 0xff) {
+            if (qdm->n_pkts > 0) {
+                av_log(s, AV_LOG_WARNING,
+                       "Out of sequence config - dropping queue\n");
+                qdm->n_pkts = 0;
+                memset(qdm->len, 0, sizeof(qdm->len));
+            }
+
+            if ((res = qdm2_parse_config(qdm, st, ++p, end)) < 0)
+                return res;
+            p += res;
+
+            /* We set codec_id to CODEC_ID_NONE initially to
+             * delay decoder initialization since extradata is
+             * carried within the RTP stream, not SDP. Here,
+             * by setting codec_id to CODEC_ID_QDM2, we are signalling
+             * to the decoder that it is OK to initialize. */
+            st->codec->codec_id = CODEC_ID_QDM2;
+        }
+
+        /* subpackets */
+        while (end - p >= 4) {
+            if ((res = qdm2_parse_subpacket(qdm, st, p, end)) < 0)
+                return res;
+            p += res;
+        }
+
+        qdm->timestamp = *timestamp;
+        if (++qdm->n_pkts < qdm->subpkts_per_block)
+            return AVERROR(EAGAIN);
+        qdm->cache = 0;
+        for (n = 0; n < 0x80; n++)
+            if (qdm->len[n] > 0)
+                qdm->cache++;
+    }
+
+    /* output the subpackets into freshly created superblock structures */
+    if (!qdm->cache || (res = qdm2_restore_block(qdm, st, pkt)) < 0)
+        return res;
+    if (--qdm->cache == 0)
+        qdm->n_pkts = 0;
+
+    *timestamp = qdm->timestamp;
+    qdm->timestamp = RTP_NOTS_VALUE;
+
+    return (qdm->cache > 0) ? 1 : 0;
+}
+
+static PayloadContext *qdm2_extradata_new(void)
+{
+    return av_mallocz(sizeof(PayloadContext));
+}
+
+static void qdm2_extradata_free(PayloadContext *qdm)
+{
+    av_free(qdm);
+}
+
+RTPDynamicProtocolHandler ff_qdm2_dynamic_handler = {
+    "X-QDM",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_NONE,
+    NULL,
+    qdm2_extradata_new,
+    qdm2_extradata_free,
+    qdm2_parse_packet,
+};