Split console_video.c so that video codecs and gui functions

are in separate files (still #include'd because of tangling in the data
structures, but this is going to be cleaned up).

The video grabbing functions still need to be moved to a separate file.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@94774 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 1009 insertions, 0 deletions

diff --git a/channels/vcodecs.c b/channels/vcodecs.c
new file mode 100644
index 000000000..197726eb9
--- /dev/null
+++ b/channels/vcodecs.c
@@ -0,0 +1,1009 @@
+/*
+ * Video codecs support for console_video.c
+ * $Revision$
+ */
+
+/*
+ * Each codec is defined by a number of callbacks
+ */
+/*! \brief initialize the encoder */
+typedef int (*encoder_init_f)(AVCodecContext *v);
+
+/*! \brief actually call the encoder */
+typedef int (*encoder_encode_f)(struct video_out_desc *v);
+
+/*! \brief encapsulate the bistream in RTP frames */
+typedef struct ast_frame *(*encoder_encap_f)(struct video_out_desc *out,
+		struct ast_frame **tail);
+
+/*! \brief inizialize the decoder */
+typedef int (*decoder_init_f)(AVCodecContext *enc_ctx);
+
+/*! \brief extract the bitstream from RTP frames and store in the fbuf.
+ * return 0 if ok, 1 on error
+ */
+typedef int (*decoder_decap_f)(struct fbuf_t *b, uint8_t *data, int len);
+
+/*! \brief actually call the decoder */
+typedef int (*decoder_decode_f)(struct video_in_desc *v, struct fbuf_t *b);
+
+struct video_codec_desc {
+	const char		*name;		/* format name */
+	int			format;		/* AST_FORMAT_* */
+	encoder_init_f		enc_init;
+	encoder_encap_f		enc_encap;
+	encoder_encode_f	enc_run;
+	decoder_init_f		dec_init;
+	decoder_decap_f		dec_decap;
+	decoder_decode_f	dec_run;
+};
+
+#ifdef debugging_only
+
+/* some debugging code to check the bitstream:
+ * declare a bit buffer, initialize it, and fetch data from it.
+ */
+struct bitbuf {
+	const uint8_t *base;
+	int	bitsize;	/* total size in bits */
+	int	ofs;	/* next bit to read */
+};
+
+static struct bitbuf bitbuf_init(const uint8_t *base, int bitsize, int start_ofs)
+{
+	struct bitbuf a;
+	a.base = base;
+	a.bitsize = bitsize;
+	a.ofs = start_ofs;
+	return a;
+}
+
+static int bitbuf_left(struct bitbuf *b)
+{
+	return b->bitsize - b->ofs;
+}
+
+static uint32_t getbits(struct bitbuf *b, int n)
+{
+	int i, ofs;
+	const uint8_t *d;
+	uint8_t mask;
+	uint32_t retval = 0;
+	if (n> 31) {
+		ast_log(LOG_WARNING, "too many bits %d, max 32\n", n);
+		return 0;
+	}
+	if (n + b->ofs > b->bitsize) {
+		ast_log(LOG_WARNING, "bitbuf overflow %d of %d\n", n + b->ofs, b->bitsize);
+		n = b->bitsize - b->ofs;
+	}
+	ofs = 7 - b->ofs % 8;	/* start from msb */
+	mask = 1 << ofs;
+	d = b->base + b->ofs / 8;	/* current byte */
+	for (i=0 ; i < n; i++) {
+		retval += retval + (*d & mask ? 1 : 0);	/* shift in new byte */
+		b->ofs++;
+		mask >>= 1;
+		if (mask == 0) {
+			d++;
+			mask = 0x80;
+		}
+	}
+	return retval;
+}
+
+static void check_h261(struct fbuf_t *b)
+{
+	struct bitbuf a = bitbuf_init(b->data, b->used * 8, 0);
+	uint32_t x, y;
+	
+	x = getbits(&a, 20);	/* PSC, 0000 0000 0000 0001 0000 */
+	if (x != 0x10) {
+		ast_log(LOG_WARNING, "bad PSC 0x%x\n", x);
+		return;
+	}
+	x = getbits(&a, 5);	/* temporal reference */
+	y = getbits(&a, 6);	/* ptype */
+	if (0)
+	ast_log(LOG_WARNING, "size %d TR %d PTY spl %d doc %d freeze %d %sCIF hi %d\n",
+		b->used,
+		x,
+		(y & 0x20) ? 1 : 0,
+		(y & 0x10) ? 1 : 0,
+		(y & 0x8) ? 1 : 0,
+		(y & 0x4) ? "" : "Q",
+		(y & 0x2) ? 1:0);
+	while ( (x = getbits(&a, 1)) == 1)
+		ast_log(LOG_WARNING, "PSPARE 0x%x\n", getbits(&a, 8));
+	// ast_log(LOG_WARNING, "PSPARE 0 - start GOB LAYER\n");
+	while ( (x = bitbuf_left(&a)) > 0) {
+		// ast_log(LOG_WARNING, "GBSC %d bits left\n", x);
+		x = getbits(&a, 16); /* GBSC 0000 0000 0000 0001 */
+		if (x != 0x1) {
+			ast_log(LOG_WARNING, "bad GBSC 0x%x\n", x);
+			break;
+		}
+		x = getbits(&a, 4);	/* group number */
+		y = getbits(&a, 5);	/* gquant */
+		if (x == 0) {
+			ast_log(LOG_WARNING, "  bad GN %d\n", x);
+			break;
+		}
+		while ( (x = getbits(&a, 1)) == 1)
+			ast_log(LOG_WARNING, "GSPARE 0x%x\n", getbits(&a, 8));
+		while ( (x = bitbuf_left(&a)) > 0) { /* MB layer */
+			break;
+		}
+	}
+}
+
+void dump_buf(struct fbuf_t *b);
+void dump_buf(struct fbuf_t *b)
+{
+	int i, x, last2lines;
+	char buf[80];
+
+	last2lines = (b->used - 16) & ~0xf;
+	ast_log(LOG_WARNING, "buf size %d of %d\n", b->used, b->size);
+	for (i = 0; i < b->used; i++) {
+		x = i & 0xf;
+		if ( x == 0) {	/* new line */
+			if (i != 0)
+				ast_log(LOG_WARNING, "%s\n", buf);
+			bzero(buf, sizeof(buf));
+			sprintf(buf, "%04x: ", i);
+		}
+		sprintf(buf + 6 + x*3, "%02x ", b->data[i]);
+		if (i > 31 && i < last2lines)
+			i = last2lines - 1;
+	}
+	if (buf[0])
+		ast_log(LOG_WARNING, "%s\n", buf);
+}
+#endif /* debugging_only */
+/*
+ * Here starts the glue code for the various supported video codecs.
+ * For each of them, we need to provide routines for initialization,
+ * calling the encoder, encapsulating the bitstream in ast_frames,
+ * extracting payload from ast_frames, and calling the decoder.
+ */
+
+/*--- h263+ support --- */
+
+/*! \brief initialization of h263p */
+static int h263p_enc_init(AVCodecContext *enc_ctx)
+{
+	/* modes supported are
+	- Unrestricted Motion Vector (annex D)
+	- Advanced Prediction (annex F)
+	- Advanced Intra Coding (annex I)
+	- Deblocking Filter (annex J)
+	- Slice Structure (annex K)
+	- Alternative Inter VLC (annex S)
+	- Modified Quantization (annex T)
+	*/
+	enc_ctx->flags |=CODEC_FLAG_H263P_UMV; /* annex D */
+	enc_ctx->flags |=CODEC_FLAG_AC_PRED; /* annex f ? */
+	enc_ctx->flags |=CODEC_FLAG_H263P_SLICE_STRUCT; /* annex k */
+	enc_ctx->flags |= CODEC_FLAG_H263P_AIC; /* annex I */
+
+	return 0;
+}
+
+
+/*
+ * Create RTP/H.263 fragments to avoid IP fragmentation. We fragment on a
+ * PSC or a GBSC, but if we don't find a suitable place just break somewhere.
+ * Everything is byte-aligned.
+ */
+static struct ast_frame *h263p_encap(struct video_out_desc *out,
+	struct ast_frame **tail)
+{
+	struct ast_frame *cur = NULL, *first = NULL;
+	uint8_t *d = out->enc_out.data;
+	int len = out->enc_out.used;
+	int l = len; /* size of the current fragment. If 0, must look for a psc */
+
+	for (;len > 0; len -= l, d += l) {
+		uint8_t *data;
+		struct ast_frame *f;
+		int i, h;
+
+		if (len >= 3 && d[0] == 0 && d[1] == 0 && d[2] >= 0x80) {
+			/* we are starting a new block, so look for a PSC. */
+			for (i = 3; i < len - 3; i++) {
+				if (d[i] == 0 && d[i+1] == 0 && d[i+2] >= 0x80) {
+					l = i;
+					break;
+				}
+			}
+		}
+		if (l > out->mtu || l > len) { /* psc not found, split */
+			l = MIN(len, out->mtu);
+		}
+		if (l < 1 || l > out->mtu) {
+			ast_log(LOG_WARNING, "--- frame error l %d\n", l);
+			break;
+		}
+		
+		if (d[0] == 0 && d[1] == 0) { /* we start with a psc */
+			h = 0;
+		} else { /* no psc, create a header */
+			h = 2;
+		}
+
+		f = create_video_frame(d, d+l, AST_FORMAT_H263_PLUS, h, cur);
+		if (!f)
+			break;
+
+		data = f->data;
+		if (h == 0) {	/* we start with a psc */
+			data[0] |= 0x04;	// set P == 1, and we are done
+		} else {	/* no psc, create a header */
+			data[0] = data[1] = 0;	// P == 0
+		}
+
+		if (!cur)
+			first = f;
+		cur = f;
+	}
+
+	if (cur)
+		cur->subclass |= 1; // RTP Marker
+
+	*tail = cur;	/* end of the list */
+	return first;
+}
+
+/*! \brief extract the bitstreem from the RTP payload.
+ * This is format dependent.
+ * For h263+, the format is defined in RFC 2429
+ * and basically has a fixed 2-byte header as follows:
+ * 5 bits	RR	reserved, shall be 0
+ * 1 bit	P	indicate a start/end condition,
+ *			in which case the payload should be prepended
+ *			by two zero-valued bytes.
+ * 1 bit	V	there is an additional VRC header after this header
+ * 6 bits	PLEN	length in bytes of extra picture header
+ * 3 bits	PEBIT	how many bits to be ignored in the last byte
+ *
+ * XXX the code below is not complete.
+ */
+static int h263p_decap(struct fbuf_t *b, uint8_t *data, int len)
+{
+	int PLEN;
+
+	if (len < 2) {
+		ast_log(LOG_WARNING, "invalid framesize %d\n", len);
+		return 1;
+	}
+	PLEN = ( (data[0] & 1) << 5 ) | ( (data[1] & 0xf8) >> 3);
+
+	if (PLEN > 0) {
+		data += PLEN;
+		len -= PLEN;
+	}
+	if (data[0] & 4)	/* bit P */
+		data[0] = data[1] = 0;
+	else {
+		data += 2;
+		len -= 2;
+	}
+	return fbuf_append(b, data, len, 0, 0);	/* ignore trail bits */
+}
+
+
+/*
+ * generic encoder, used by the various protocols supported here.
+ * We assume that the buffer is empty at the beginning.
+ */
+static int ffmpeg_encode(struct video_out_desc *v)
+{
+	struct fbuf_t *b = &v->enc_out;
+	int i;
+
+	b->used = avcodec_encode_video(v->enc_ctx, b->data, b->size, v->enc_in_frame);
+	i = avcodec_encode_video(v->enc_ctx, b->data + b->used, b->size - b->used, NULL); /* delayed frames ? */
+	if (i > 0) {
+		ast_log(LOG_WARNING, "have %d more bytes\n", i);
+		b->used += i;
+	}
+	return 0;
+}
+
+/*
+ * Generic decoder, which is used by h263p, h263 and h261 as it simply
+ * invokes ffmpeg's decoder.
+ * av_parser_parse should merge a randomly chopped up stream into
+ * proper frames. After that, if we have a valid frame, we decode it
+ * until the entire frame is processed.
+ */
+static int ffmpeg_decode(struct video_in_desc *v, struct fbuf_t *b)
+{
+	uint8_t *src = b->data;
+	int srclen = b->used;
+	int full_frame = 0;
+
+	if (srclen == 0)	/* no data */
+		return 0;
+	while (srclen) {
+		uint8_t *data;
+		int datalen, ret;
+		int len = av_parser_parse(v->parser, v->dec_ctx, &data, &datalen, src, srclen, 0, 0);
+
+		src += len;
+		srclen -= len;
+		/* The parser might return something it cannot decode, so it skips
+		 * the block returning no data
+		 */
+		if (data == NULL || datalen == 0)
+			continue;
+		ret = avcodec_decode_video(v->dec_ctx, v->d_frame, &full_frame, data, datalen);
+		if (full_frame == 1)	/* full frame */
+			break;
+		if (ret < 0) {
+			ast_log(LOG_NOTICE, "Error decoding\n");
+			break;
+		}
+	}
+	if (srclen != 0)	/* update b with leftover data */
+		bcopy(src, b->data, srclen);
+	b->used = srclen;
+	b->ebit = 0;
+	return full_frame;
+}
+
+static struct video_codec_desc h263p_codec = {
+	.name = "h263p",
+	.format = AST_FORMAT_H263_PLUS,
+	.enc_init = h263p_enc_init,
+	.enc_encap = h263p_encap,
+	.enc_run = ffmpeg_encode,
+	.dec_init = NULL,
+	.dec_decap = h263p_decap,
+	.dec_run = ffmpeg_decode
+};
+
+/*--- Plain h263 support --------*/
+
+static int h263_enc_init(AVCodecContext *enc_ctx)
+{
+	/* XXX check whether these are supported */
+	enc_ctx->flags |= CODEC_FLAG_H263P_UMV;
+	enc_ctx->flags |= CODEC_FLAG_H263P_AIC;
+	enc_ctx->flags |= CODEC_FLAG_H263P_SLICE_STRUCT;
+	enc_ctx->flags |= CODEC_FLAG_AC_PRED;
+
+	return 0;
+}
+
+/*
+ * h263 encapsulation is specified in RFC2190. There are three modes
+ * defined (A, B, C), with 4, 8 and 12 bytes of header, respectively.
+ * The header is made as follows
+ *     0.....................|.......................|.............|....31
+ *	F:1 P:1 SBIT:3 EBIT:3 SRC:3 I:1 U:1 S:1 A:1 R:4 DBQ:2 TRB:3 TR:8
+ * FP = 0- mode A, (only one word of header)
+ * FP = 10 mode B, and also means this is an I or P frame
+ * FP = 11 mode C, and also means this is a PB frame.
+ * SBIT, EBIT nuber of bits to ignore at beginning (msbits) and end (lsbits)
+ * SRC  bits 6,7,8 from the h263 PTYPE field
+ * I = 0 intra-coded, 1 = inter-coded (bit 9 from PTYPE)
+ * U = 1 for Unrestricted Motion Vector (bit 10 from PTYPE)
+ * S = 1 for Syntax Based Arith coding (bit 11 from PTYPE)
+ * A = 1 for Advanced Prediction (bit 12 from PTYPE)
+ * R = reserved, must be 0
+ * DBQ = differential quantization, DBQUANT from h263, 0 unless we are using
+ *	PB frames
+ * TRB = temporal reference for bframes, also 0 unless this is a PB frame
+ * TR = temporal reference for P frames, also 0 unless PB frame.
+ *
+ * Mode B and mode C description omitted.
+ *
+ * An RTP frame can start with a PSC 0000 0000 0000 0000 1000 0
+ * or with a GBSC, which also has the first 17 bits as a PSC.
+ * Note - PSC are byte-aligned, GOB not necessarily. PSC start with
+ *	PSC:22 0000 0000 0000 0000 1000 00 	picture start code
+ *	TR:8   .... ....			temporal reference
+ *      PTYPE:13 or more 			ptype...
+ * If we don't fragment a GOB SBIT and EBIT = 0.
+ * reference, 8 bit) 
+ * 
+ * The assumption below is that we start with a PSC.
+ */
+static struct ast_frame *h263_encap(struct video_out_desc *out,
+		struct ast_frame **tail)
+{
+	uint8_t *d = out->enc_out.data;
+	int start = 0, i, len = out->enc_out.used;
+	struct ast_frame *f, *cur = NULL, *first = NULL;
+	const int pheader_len = 4;	/* Use RFC-2190 Mode A */
+	uint8_t h263_hdr[12];	/* worst case, room for a type c header */
+	uint8_t *h = h263_hdr;	/* shorthand */
+
+#define H263_MIN_LEN	6
+	if (len < H263_MIN_LEN)	/* unreasonably small */
+		return NULL;
+
+	bzero(h263_hdr, sizeof(h263_hdr));
+	/* Now set the header bytes. Only type A by now,
+	 * and h[0] = h[2] = h[3] = 0 by default.
+	 * PTYPE starts 30 bits in the picture, so the first useful
+	 * bit for us is bit 36 i.e. within d[4] (0 is the msbit).
+	 * SRC = d[4] & 0x1c goes into data[1] & 0xe0
+	 * I   = d[4] & 0x02 goes into data[1] & 0x10
+	 * U   = d[4] & 0x01 goes into data[1] & 0x08
+	 * S   = d[5] & 0x80 goes into data[1] & 0x04
+	 * A   = d[5] & 0x40 goes into data[1] & 0x02
+	 * R   = 0           goes into data[1] & 0x01
+	 * Optimizing it, we have
+	 */
+	h[1] = ( (d[4] & 0x1f) << 3 ) |	/* SRC, I, U */
+		( (d[5] & 0xc0) >> 5 );		/* S, A, R */
+
+	/* now look for the next PSC or GOB header. First try to hit
+	 * a '0' byte then look around for the 0000 0000 0000 0000 1 pattern
+	 * which is both in the PSC and the GBSC.
+	 */
+	for (i = H263_MIN_LEN, start = 0; start < len; start = i, i += 3) {
+		//ast_log(LOG_WARNING, "search at %d of %d/%d\n", i, start, len);
+		for (; i < len ; i++) {
+			uint8_t x, rpos, lpos;
+			int rpos_i;	/* index corresponding to rpos */
+			if (d[i] != 0)		/* cannot be in a GBSC */
+				continue;
+			if (i > len - 1)
+				break;
+			x = d[i+1];
+			if (x == 0)	/* next is equally good */
+				continue;
+			/* see if around us we can make 16 '0' bits for the GBSC.
+			 * Look for the first bit set on the right, and then
+			 * see if we have enough 0 on the left.
+			 * We are guaranteed to end before rpos == 0
+			 */
+			for (rpos = 0x80, rpos_i = 8; rpos; rpos >>= 1, rpos_i--)
+				if (x & rpos)	/* found the '1' bit in GBSC */
+					break;
+			x = d[i-1];		/* now look behind */
+			for (lpos = rpos; lpos ; lpos >>= 1)
+				if (x & lpos)	/* too early, not a GBSC */
+					break;
+			if (lpos)		/* as i said... */
+				continue;
+			/* now we have a GBSC starting somewhere in d[i-1],
+			 * but it might be not byte-aligned
+			 */
+			if (rpos == 0x80) {	/* lucky case */
+				i = i - 1;
+			} else {	/* XXX to be completed */
+				ast_log(LOG_WARNING, "unaligned GBSC 0x%x %d\n",
+					rpos, rpos_i);
+			}
+			break;
+		}
+		/* This frame is up to offset i (not inclusive).
+		 * We do not split it yet even if larger than MTU.
+		 */
+		f = create_video_frame(d + start, d+i, AST_FORMAT_H263,
+				pheader_len, cur);
+
+		if (!f)
+			break;
+		bcopy(h, f->data, 4);	/* copy the h263 header */
+		/* XXX to do: if not aligned, fix sbit and ebit,
+		 * then move i back by 1 for the next frame
+		 */
+		if (!cur)
+			first = f;
+		cur = f;
+	}
+
+	if (cur)
+		cur->subclass |= 1;	// RTP Marker
+
+	*tail = cur;
+	return first;
+}
+
+/* XXX We only drop the header here, but maybe we need more. */
+static int h263_decap(struct fbuf_t *b, uint8_t *data, int len)
+{
+	if (len < 4) {
+		ast_log(LOG_WARNING, "invalid framesize %d\n", len);
+		return 1;	/* error */
+	}
+
+	if ( (data[0] & 0x80) == 0) {
+		len -= 4;
+		data += 4;
+	} else {
+		ast_log(LOG_WARNING, "unsupported mode 0x%x\n",
+			data[0]);
+		return 1;
+	}
+	return fbuf_append(b, data, len, 0, 0);	/* XXX no bit alignment support yet */
+}
+
+static struct video_codec_desc h263_codec = {
+	.name = "h263",
+	.format = AST_FORMAT_H263,
+	.enc_init = h263_enc_init,
+	.enc_encap = h263_encap,
+	.enc_run = ffmpeg_encode,
+	.dec_init = NULL,
+	.dec_decap = h263_decap,
+	.dec_run = ffmpeg_decode
+						
+};
+
+/*---- h261 support -----*/
+static int h261_enc_init(AVCodecContext *enc_ctx)
+{
+	/* It is important to set rtp_payload_size = 0, otherwise
+	 * ffmpeg in h261 mode will produce output that it cannot parse.
+	 * Also try to send I frames more frequently than with other codecs.
+	 */
+	enc_ctx->rtp_payload_size = 0; /* important - ffmpeg fails otherwise */
+
+	return 0;
+}
+
+/*
+ * The encapsulation of H261 is defined in RFC4587 which obsoletes RFC2032
+ * The bitstream is preceded by a 32-bit header word:
+ *  SBIT:3 EBIT:3 I:1 V:1 GOBN:4 MBAP:5 QUANT:5 HMVD:5 VMVD:5
+ * SBIT and EBIT are the bits to be ignored at beginning and end,
+ * I=1 if the stream has only INTRA frames - cannot change during the stream.
+ * V=0 if motion vector is not used. Cannot change.
+ * GOBN is the GOB number in effect at the start of packet, 0 if we
+ *	start with a GOB header
+ * QUANT is the quantizer in effect, 0 if we start with GOB header
+ * HMVD  reference horizontal motion vector. 10000 is forbidden
+ * VMVD  reference vertical motion vector, as above.
+ * Packetization should occur at GOB boundaries, and if not possible
+ * with MacroBlock fragmentation. However it is likely that blocks
+ * are not bit-aligned so we must take care of this.
+ */
+static struct ast_frame *h261_encap(struct video_out_desc *out,
+		struct ast_frame **tail)
+{
+	uint8_t *d = out->enc_out.data;
+	int start = 0, i, len = out->enc_out.used;
+	struct ast_frame *f, *cur = NULL, *first = NULL;
+	const int pheader_len = 4;
+	uint8_t h261_hdr[4];
+	uint8_t *h = h261_hdr;	/* shorthand */
+	int sbit = 0, ebit = 0;
+
+#define H261_MIN_LEN 10
+	if (len < H261_MIN_LEN)	/* unreasonably small */
+		return NULL;
+
+	bzero(h261_hdr, sizeof(h261_hdr));
+
+	/* Similar to the code in h263_encap, but the marker there is longer.
+	 * Start a few bytes within the bitstream to avoid hitting the marker
+	 * twice. Note we might access the buffer at len, but this is ok because
+	 * the caller has it oversized.
+	 */
+	for (i = H261_MIN_LEN, start = 0; start < len - 1; start = i, i += 4) {
+#if 0	/* test - disable packetization */
+		i = len;	/* wrong... */
+#else
+		int found = 0, found_ebit = 0;	/* last GBSC position found */
+		for (; i < len ; i++) {
+			uint8_t x, rpos, lpos;
+			if (d[i] != 0)		/* cannot be in a GBSC */
+				continue;
+			x = d[i+1];
+			if (x == 0)	/* next is equally good */
+				continue;
+			/* See if around us we find 15 '0' bits for the GBSC.
+			 * Look for the first bit set on the right, and then
+			 * see if we have enough 0 on the left.
+			 * We are guaranteed to end before rpos == 0
+			 */
+			for (rpos = 0x80, ebit = 7; rpos; ebit--, rpos >>= 1)
+				if (x & rpos)	/* found the '1' bit in GBSC */
+					break;
+			x = d[i-1];		/* now look behind */
+			for (lpos = (rpos >> 1); lpos ; lpos >>= 1)
+				if (x & lpos)	/* too early, not a GBSC */
+					break;
+			if (lpos)		/* as i said... */
+				continue;
+			/* now we have a GBSC starting somewhere in d[i-1],
+			 * but it might be not byte-aligned. Just remember it.
+			 */
+			if (i - start > out->mtu) /* too large, stop now */
+				break;
+			found_ebit = ebit;
+			found = i;
+			i += 4;	/* continue forward */
+		}
+		if (i >= len) {	/* trim if we went too forward */
+			i = len;
+			ebit = 0;	/* hopefully... should ask the bitstream ? */
+		}
+		if (i - start > out->mtu && found) {
+			/* use the previous GBSC, hope is within the mtu */
+			i = found;
+			ebit = found_ebit;
+		}
+#endif /* test */
+		if (i - start < 4)	/* XXX too short ? */
+			continue;
+		/* This frame is up to offset i (not inclusive).
+		 * We do not split it yet even if larger than MTU.
+		 */
+		f = create_video_frame(d + start, d+i, AST_FORMAT_H261,
+				pheader_len, cur);
+
+		if (!f)
+			break;
+		/* recompute header with I=0, V=1 */
+		h[0] = ( (sbit & 7) << 5 ) | ( (ebit & 7) << 2 ) | 1;
+		bcopy(h, f->data, 4);	/* copy the h261 header */
+		if (ebit)	/* not aligned, restart from previous byte */
+			i--;
+		sbit = (8 - ebit) & 7;
+		ebit = 0;
+		if (!cur)
+			first = f;
+		cur = f;
+	}
+	if (cur)
+		cur->subclass |= 1;	// RTP Marker
+
+	*tail = cur;
+	return first;
+}
+
+/*
+ * Pieces might be unaligned so we really need to put them together.
+ */
+static int h261_decap(struct fbuf_t *b, uint8_t *data, int len)
+{
+	int ebit, sbit;
+
+	if (len < 8) {
+		ast_log(LOG_WARNING, "invalid framesize %d\n", len);
+		return 1;
+	}
+	sbit = (data[0] >> 5) & 7;
+	ebit = (data[0] >> 2) & 7;
+	len -= 4;
+	data += 4;
+	return fbuf_append(b, data, len, sbit, ebit);
+}
+
+static struct video_codec_desc h261_codec = {
+	.name = "h261",
+	.format = AST_FORMAT_H261,
+	.enc_init = h261_enc_init,
+	.enc_encap = h261_encap,
+	.enc_run = ffmpeg_encode,
+	.dec_init = NULL,
+	.dec_decap = h261_decap,
+	.dec_run = ffmpeg_decode
+};
+
+/* mpeg4 support */
+static int mpeg4_enc_init(AVCodecContext *enc_ctx)
+{
+#if 0
+	//enc_ctx->flags |= CODEC_FLAG_LOW_DELAY; /*don't use b frames ?*/
+	enc_ctx->flags |= CODEC_FLAG_AC_PRED;
+	enc_ctx->flags |= CODEC_FLAG_H263P_UMV;
+	enc_ctx->flags |= CODEC_FLAG_QPEL;
+	enc_ctx->flags |= CODEC_FLAG_4MV;
+	enc_ctx->flags |= CODEC_FLAG_GMC;
+	enc_ctx->flags |= CODEC_FLAG_LOOP_FILTER;
+	enc_ctx->flags |= CODEC_FLAG_H263P_SLICE_STRUCT;
+#endif
+	enc_ctx->rtp_payload_size = 0; /* important - ffmpeg fails otherwise */
+	return 0;
+}
+
+/* simplistic encapsulation - just split frames in mtu-size units */
+static struct ast_frame *mpeg4_encap(struct  video_out_desc *out,
+	struct ast_frame **tail)
+{
+	struct ast_frame *f, *cur = NULL, *first = NULL;
+	uint8_t *d = out->enc_out.data;
+	uint8_t *end = d+out->enc_out.used;
+	int len;
+
+	for (;d < end; d += len, cur = f) {
+		len = MIN(out->mtu, end-d);
+		f = create_video_frame(d, d+len, AST_FORMAT_MP4_VIDEO, 0, cur);
+		if (!f)
+			break;
+		if (!first)
+			first = f;
+	}
+	if (cur)
+		cur->subclass |= 1;
+	*tail = cur;
+	return first;
+}
+
+static int mpeg4_decap(struct fbuf_t *b, uint8_t *data, int len)
+{
+	return fbuf_append(b, data, len, 0, 0);
+}
+
+static int mpeg4_decode(struct video_in_desc *v, struct fbuf_t *b)
+{
+	int full_frame = 0, datalen = b->used;
+	int ret = avcodec_decode_video(v->dec_ctx, v->d_frame, &full_frame,
+		b->data, datalen);
+	if (ret < 0) {
+		ast_log(LOG_NOTICE, "Error decoding\n");
+		ret = datalen; /* assume we used everything. */
+	}
+	datalen -= ret;
+	if (datalen > 0)	/* update b with leftover bytes */
+		bcopy(b->data + ret, b->data, datalen);
+	b->used = datalen;
+	b->ebit = 0;
+	return full_frame;
+}
+
+static struct video_codec_desc mpeg4_codec = {
+	.name = "mpeg4",
+	.format = AST_FORMAT_MP4_VIDEO,
+	.enc_init = mpeg4_enc_init,
+	.enc_encap = mpeg4_encap,
+	.enc_run = ffmpeg_encode,
+	.dec_init = NULL,
+	.dec_decap = mpeg4_decap,
+	.dec_run = mpeg4_decode
+};
+
+static int h264_enc_init(AVCodecContext *enc_ctx)
+{
+	enc_ctx->flags |= CODEC_FLAG_TRUNCATED;
+	//enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
+	//enc_ctx->flags2 |= CODEC_FLAG2_FASTPSKIP;
+	/* TODO: Maybe we need to add some other flags */
+	enc_ctx->rtp_mode = 0;
+	enc_ctx->rtp_payload_size = 0;
+	enc_ctx->bit_rate_tolerance = enc_ctx->bit_rate;
+	return 0;
+}
+
+static int h264_dec_init(AVCodecContext *dec_ctx)
+{
+	dec_ctx->flags |= CODEC_FLAG_TRUNCATED;
+
+	return 0;
+}
+
+/*
+ * The structure of a generic H.264 stream is:
+ * - 0..n 0-byte(s), unused, optional. one zero-byte is always present
+ *   in the first NAL before the start code prefix.
+ * - start code prefix (3 bytes): 0x000001
+ *   (the first bytestream has a 
+ *   like these 0x00000001!)
+ * - NAL header byte ( F[1] | NRI[2] | Type[5] ) where type != 0
+ * - byte-stream
+ * - 0..n 0-byte(s) (padding, unused).
+ * Segmentation in RTP only needs to be done on start code prefixes.
+ * If fragments are too long... we don't support it yet.
+ * - encapsulate (or fragment) the byte-stream (with NAL header included)
+ */
+static struct ast_frame *h264_encap(struct video_out_desc *out,
+	struct ast_frame **tail)
+{
+	struct ast_frame *f = NULL, *cur = NULL, *first = NULL;
+	uint8_t *d, *start = out->enc_out.data;
+	uint8_t *end = start + out->enc_out.used;
+
+	/* Search the first start code prefix - ITU-T H.264 sec. B.2,
+	 * and move start right after that, on the NAL header byte.
+	 */
+#define HAVE_NAL(x) (x[-4] == 0 && x[-3] == 0 && x[-2] == 0 && x[-1] == 1)
+	for (start += 4; start < end; start++) {
+		int ty = start[0] & 0x1f;
+		if (HAVE_NAL(start) && ty != 0 && ty != 31)
+			break;
+	}
+	/* if not found, or too short, we just skip the next loop and are done. */
+
+	/* Here follows the main loop to create frames. Search subsequent start
+	 * codes, and then possibly fragment the unit into smaller fragments.
+	 */
+   for (;start < end - 4; start = d) {
+	int size;		/* size of current block */
+	uint8_t hdr[2];		/* add-on header when fragmenting */
+	int ty = 0;
+
+	/* now search next nal */
+	for (d = start + 4; d < end; d++) {
+		ty = d[0] & 0x1f;
+		if (HAVE_NAL(d))
+			break;	/* found NAL */
+	}
+	/* have a block to send. d past the start code unless we overflow */
+	if (d >= end) {	/* NAL not found */
+		d = end + 4;
+	} else if (ty == 0 || ty == 31) { /* found but invalid type, skip */
+		ast_log(LOG_WARNING, "skip invalid nal type %d at %d of %d\n",
+			ty, d - out->enc_out.data, out->enc_out.used);
+		continue;
+	}
+
+	size = d - start - 4;	/* don't count the end */
+
+	if (size < out->mtu) {	// test - don't fragment
+		// Single NAL Unit
+		f = create_video_frame(start, d - 4, AST_FORMAT_H264, 0, cur);
+		if (!f)
+			break;
+		if (!first)
+			first = f;
+
+		cur = f;
+		continue;
+	}
+
+	// Fragmented Unit (Mode A: no DON, very weak)
+	hdr[0] = (*start & 0xe0) | 28;	/* mark as a fragmentation unit */
+	hdr[1] = (*start++ & 0x1f) | 0x80 ;	/* keep type and set START bit */
+	size--;		/* skip the NAL header */
+	while (size) {
+		uint8_t *data;
+		int frag_size = MIN(size, out->mtu);
+
+		f = create_video_frame(start, start+frag_size, AST_FORMAT_H264, 2, cur);
+		if (!f)
+			break;
+		size -= frag_size;	/* skip this data block */
+		start += frag_size;
+
+		data = f->data;
+		data[0] = hdr[0];
+		data[1] = hdr[1] | (size == 0 ? 0x40 : 0);	/* end bit if we are done */
+		hdr[1] &= ~0x80;	/* clear start bit for subsequent frames */
+		if (!first)
+			first = f;
+		cur = f;
+	}
+    }
+
+	if (cur)
+		cur->subclass |= 1;     // RTP Marker
+
+	*tail = cur;
+
+	return first;
+}
+
+static int h264_decap(struct fbuf_t *b, uint8_t *data, int len)
+{
+	/* Start Code Prefix (Annex B in specification) */
+	uint8_t scp[] = { 0x00, 0x00, 0x00, 0x01 };
+	int retval = 0;
+	int type, ofs = 0;
+
+	if (len < 2) {
+		ast_log(LOG_WARNING, "--- invalid len %d\n", len);
+		return 1;
+	}
+	/* first of all, check if the packet has F == 0 */
+	if (data[0] & 0x80) {
+		ast_log(LOG_WARNING, "--- forbidden packet; nal: %02x\n",
+			data[0]);
+		return 1;
+	}
+
+	type = data[0] & 0x1f;
+	switch (type) {
+	case 0:
+	case 31:
+		ast_log(LOG_WARNING, "--- invalid type: %d\n", type);
+		return 1;
+	case 24:
+	case 25:
+	case 26:
+	case 27:
+	case 29:
+		ast_log(LOG_WARNING, "--- encapsulation not supported : %d\n", type);
+		return 1;
+	case 28:	/* FU-A Unit */
+		if (data[1] & 0x80) { // S == 1, import F and NRI from next
+			data[1] &= 0x1f;	/* preserve type */
+			data[1] |= (data[0] & 0xe0);	/* import F & NRI */
+			retval = fbuf_append(b, scp, sizeof(scp), 0, 0);
+			ofs = 1;
+		} else {
+			ofs = 2;
+		}
+		break;
+	default:	/* From 1 to 23 (Single NAL Unit) */
+		retval = fbuf_append(b, scp, sizeof(scp), 0, 0);
+	}
+	if (!retval)
+		retval = fbuf_append(b, data + ofs, len - ofs, 0, 0);
+	if (retval)
+		ast_log(LOG_WARNING, "result %d\n", retval);
+	return retval;
+}
+
+static struct video_codec_desc h264_codec = {
+	.name = "h264",
+	.format = AST_FORMAT_H264,
+	.enc_init = h264_enc_init,
+	.enc_encap = h264_encap,
+	.enc_run = ffmpeg_encode,
+	.dec_init = h264_dec_init,
+	.dec_decap = h264_decap,
+	.dec_run = ffmpeg_decode
+};
+
+/*
+ * Table of translation between asterisk and ffmpeg formats.
+ * We need also a field for read and write (encoding and decoding), because
+ * e.g. H263+ uses different codec IDs in ffmpeg when encoding or decoding.
+ */
+struct _cm {    /* map ffmpeg codec types to asterisk formats */
+	uint32_t	ast_format;	/* 0 is a terminator */
+	enum CodecID	codec;
+	enum { CM_RD = 1, CM_WR = 2, CM_RDWR = 3 } rw;  /* read or write or both ? */
+	struct video_codec_desc *codec_desc;
+};
+
+static struct _cm video_formats[] = {
+        { AST_FORMAT_H263_PLUS, CODEC_ID_H263,  CM_RD }, /* incoming H263P ? */
+        { AST_FORMAT_H263_PLUS, CODEC_ID_H263P, CM_WR },
+        { AST_FORMAT_H263,      CODEC_ID_H263,  CM_RD },
+        { AST_FORMAT_H263,      CODEC_ID_H263,  CM_WR },
+        { AST_FORMAT_H261,      CODEC_ID_H261,  CM_RDWR },
+        { AST_FORMAT_H264,      CODEC_ID_H264,  CM_RDWR },
+        { AST_FORMAT_MP4_VIDEO, CODEC_ID_MPEG4, CM_RDWR },
+        { 0,                    0, 0 },
+};
+                
+
+/*! \brief map an asterisk format into an ffmpeg one */
+static enum CodecID map_video_format(uint32_t ast_format, int rw)
+{
+	struct _cm *i;
+
+	for (i = video_formats; i->ast_format != 0; i++)
+		if (ast_format & i->ast_format && rw & i->rw && rw & i->rw)
+			return i->codec;
+	return CODEC_ID_NONE;
+}
+
+/* pointers to supported codecs. We assume the first one to be non null. */
+static struct video_codec_desc *supported_codecs[] = {
+	&h263p_codec,
+	&h264_codec,
+	&h263_codec,
+	&h261_codec,
+	&mpeg4_codec,
+	NULL
+};
+
+/*
+ * Map the AST_FORMAT to the library. If not recognised, fail.
+ * This is useful in the input path where we get frames.
+ */
+static struct video_codec_desc *map_video_codec(int fmt)
+{
+	int i;
+
+	for (i = 0; supported_codecs[i]; i++)
+		if (fmt == supported_codecs[i]->format) {
+			ast_log(LOG_WARNING, "using %s for format 0x%x\n",
+				supported_codecs[i]->name, fmt);
+			return supported_codecs[i];
+		}
+	return NULL;
+}
+
+/*------ end codec specific code -----*/