@@ -1,7 +1,8 @@

 /*

  * Dirac parser

  *

- * Copyright (c) 2007 Marco Gerards <marco@gnu.org>

+ * Copyright (c) 2007-2008 Marco Gerards <marco@gnu.org>

+ * Copyright (c) 2008 BBC, Anuradha Suraparaju <asuraparaju@gmail.com>

  *

  * This file is part of FFmpeg.

  *

@@ -34,42 +35,200 @@

  * Finds the end of the current frame in the bitstream.

  * @return the position of the first byte of the next frame or -1

  */

-static int find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)

+typedef struct DiracParseContext {

+    int state;

+    int is_synced;

+    int sync_offset;

+    int header_bytes_needed;

+    int overread_index;

+    int buffer_size;

+    int index;

+    uint8_t *buffer;

+    int dirac_unit_size;

+    uint8_t *dirac_unit;

+} DiracParseContext;

+

+static int find_frame_end(DiracParseContext *pc,

+                          const uint8_t *buf, int buf_size)

 {

     uint32_t state = pc->state;

-    int i;

-

-    for (i = 0; i < buf_size; i++) {

-        state = (state << 8) | buf[i];

-        if (state == DIRAC_PARSE_INFO_PREFIX) {

-            pc->frame_start_found ^= 1;

-            if (!pc->frame_start_found) {

-                pc->state = -1;

-                return i - 3;

+    int i = 0;

+

+    if (!pc->is_synced) {

+        for (i = 0; i < buf_size; i++) {

+            state = (state << 8) | buf[i];

+            if (state == DIRAC_PARSE_INFO_PREFIX) {

+                state                   = -1;

+                pc->is_synced           = 1;

+                pc->header_bytes_needed = 9;

+                pc->sync_offset         = i;

+                break;

             }

         }

     }

+    if (pc->is_synced) {

+        pc->sync_offset = 0;

+        for (; i < buf_size; i++) {

+            if (state == DIRAC_PARSE_INFO_PREFIX) {

+                if ((buf_size-i) >= pc->header_bytes_needed) {

+                    pc->state = -1;

+                    return i + pc->header_bytes_needed;

+                } else {

+                    pc->header_bytes_needed = 9-(buf_size-i);

+                    break;

+                }

+            } else

+              state = (state << 8) | buf[i];

+        }

+    }

     pc->state = state;

+    return -1;

+}

+

+typedef struct DiracParseUnit

+{

+    int next_pu_offset;

+    int prev_pu_offset;

+    uint8_t pu_type;

+} DiracParseUnit;

+

+static int unpack_parse_unit(DiracParseUnit *pu, DiracParseContext *pc,

+                             int offset)

+{

+    uint8_t *start = pc->buffer + offset;

+    uint8_t *end   = pc->buffer + pc->index;

+    if (start < pc->buffer || (start+13 > end))

+        return 0;

+    pu->pu_type = start[4];

+

+    pu->next_pu_offset = AV_RB32(start+5);

+    pu->prev_pu_offset = AV_RB32(start+9);

+

+    if (pu->pu_type == 0x10 && pu->next_pu_offset == 0)

+        pu->next_pu_offset = 13;

+

+    return 1;

+}

+

+static int dirac_combine_frame(AVCodecParserContext *s, AVCodecContext *avctx,

+                               int next, const uint8_t **buf, int *buf_size)

+{

+    int parse_timing_info = (s->pts == AV_NOPTS_VALUE &&

+                             s->dts == AV_NOPTS_VALUE);

+    DiracParseContext *pc = s->priv_data;

+

+    if (pc->overread_index) {

+        memcpy(pc->buffer, pc->buffer + pc->overread_index,

+               pc->index - pc->overread_index);

+        pc->index -= pc->overread_index;

+        pc->overread_index = 0;

+        if (*buf_size == 0 && pc->buffer[4] == 0x10) {

+            *buf      = pc->buffer;

+            *buf_size = pc->index;

+            return 0;

+        }

+    }

+

+    if ( next == -1) {

+        /* Found a possible frame start but not a frame end */

+        void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,

+                                           pc->index + (*buf_size -

+                                                        pc->sync_offset));

+        pc->buffer = new_buffer;

+        memcpy(pc->buffer+pc->index, (*buf + pc->sync_offset),

+               *buf_size - pc->sync_offset);

+        pc->index += *buf_size - pc->sync_offset;

+        return -1;

+    } else {

+        /* Found a possible frame start and a  possible frame end */

+        DiracParseUnit pu1, pu;

+        void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,

+                                           pc->index + next);

+        pc->buffer = new_buffer;

+        memcpy(pc->buffer + pc->index, *buf, next);

+        pc->index += next;

-    return END_NOT_FOUND;

+        /* Need to check if we have a valid Parse Unit. We can't go by the

+         * sync pattern 'BBCD' alone because arithmetic coding of the residual

+         * and motion data can cause the pattern triggering a false start of

+         * frame. So check if the previous parse offset of the next parse unit

+         * is equal to the next parse offset of the current parse unit then

+         * we can be pretty sure that we have a valid parse unit */

+        if (!unpack_parse_unit(&pu1, pc, pc->index - 13)                     ||

+            !unpack_parse_unit(&pu, pc, pc->index - 13 - pu1.prev_pu_offset) ||

+            pu.next_pu_offset != pu1.prev_pu_offset) {

+            pc->index -= 9;

+            *buf_size = next-9;

+            pc->header_bytes_needed = 9;

+            return -1;

+        }

+

+        /* All non-frame data must be accompanied by frame data. This is to

+         * ensure that pts is set correctly. So if the current parse unit is

+         * not frame data, wait for frame data to come along */

+

+        pc->dirac_unit = pc->buffer + pc->index - 13 -

+                         pu1.prev_pu_offset - pc->dirac_unit_size;

+

+        pc->dirac_unit_size += pu.next_pu_offset;

+

+        if ((pu.pu_type&0x08) != 0x08) {

+            pc->header_bytes_needed = 9;

+            *buf_size = next;

+            return -1;

+        }

+

+        /* Get the picture number to set the pts and dts*/

+        if (parse_timing_info) {

+            uint8_t *cur_pu = pc->buffer +

+                              pc->index - 13 - pu1.prev_pu_offset;

+            int pts =  AV_RB32(cur_pu + 13);

+            if (s->last_pts == 0 && s->last_dts == 0)

+                s->dts = pts - 1;

+            else

+                s->dts = s->last_dts+1;

+            s->pts = pts;

+            if (!avctx->has_b_frames && (cur_pu[4] & 0x03))

+                avctx->has_b_frames = 1;

+        }

+        if (avctx->has_b_frames && s->pts == s->dts)

+             s->pict_type = FF_B_TYPE;

+

+        /* Finally have a complete Dirac data unit */

+        *buf      = pc->dirac_unit;

+        *buf_size = pc->dirac_unit_size;

+

+        pc->dirac_unit_size     = 0;

+        pc->overread_index      = pc->index-13;

+        pc->header_bytes_needed = 9;

+    }

+    return next;

 }

 static int dirac_parse(AVCodecParserContext *s, AVCodecContext *avctx,

                        const uint8_t **poutbuf, int *poutbuf_size,

                        const uint8_t *buf, int buf_size)

 {

-    ParseContext *pc = s->priv_data;

+    DiracParseContext *pc = s->priv_data;

     int next;

+    *poutbuf = NULL;

+    *poutbuf_size = 0;

+

     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {

         next = buf_size;

-    }else{

+        *poutbuf = buf;

+        *poutbuf_size = buf_size;

+        /* Assume that data has been packetized into an encapsulation unit. */

+    } else {

         next = find_frame_end(pc, buf, buf_size);

+        if (!pc->is_synced && next == -1) {

+            /* No frame start found yet. So throw away the entire buffer. */

+            return buf_size;

+        }

-        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {

-            *poutbuf = NULL;

-            *poutbuf_size = 0;

+        if (dirac_combine_frame(s, avctx, next, &buf, &buf_size) < 0) {

             return buf_size;

         }

     }

@@ -79,10 +238,18 @@ static int dirac_parse(AVCodecParserContext *s, AVCodecContext *avctx,

     return next;

 }

+static void dirac_parse_close(AVCodecParserContext *s)

+{

+    DiracParseContext *pc = s->priv_data;

+

+    if (pc->buffer_size > 0)

+        av_free(pc->buffer);

+}

+

 AVCodecParser dirac_parser = {

     { CODEC_ID_DIRAC },

-    sizeof(ParseContext),

+    sizeof(DiracParseContext),

     NULL,

     dirac_parse,

-    ff_parse_close,

+    dirac_parse_close,

 };

@@ -88,10 +88,12 @@ static int libdirac_decode_frame(AVCodecContext *avccontext,

     *data_size = 0;

-    if (buf_size>0)

+    if (buf_size>0) {

         /* set data to decode into buffer */

         dirac_buffer (p_dirac_params->p_decoder, buf, buf+buf_size);

-

+        if ((buf[4] &0x08) == 0x08 && (buf[4] & 0x03))

+            avccontext->has_b_frames = 1;

+    }

     while (1) {

          /* parse data and process result */

         DecoderState state = dirac_parse (p_dirac_params->p_decoder);

@@ -235,6 +235,9 @@ static int libschroedinger_decode_frame(AVCodecContext *avccontext,

     do {

         if ((enc_buf = FfmpegFindNextSchroParseUnit(&parse_ctx))) {

             /* Push buffer into decoder. */

+            if (SCHRO_PARSE_CODE_IS_PICTURE(enc_buf->data[4]) &&

+                SCHRO_PARSE_CODE_NUM_REFS(enc_buf->data[4]) > 0)

+                avccontext->has_b_frames = 1;

             state = schro_decoder_push (decoder, enc_buf);

             if (state == SCHRO_DECODER_FIRST_ACCESS_UNIT)

                   libschroedinger_handle_first_access_unit(avccontext);