move mpegvideo_parser in it's own file

Originally committed as revision 8901 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 185 insertions, 0 deletions

diff --git a/libavcodec/mpegvideo_parser.c b/libavcodec/mpegvideo_parser.c
new file mode 100644
index 0000000000..a015b1617c
--- /dev/null
+++ b/libavcodec/mpegvideo_parser.c
@@ -0,0 +1,185 @@
+/*
+ * MPEG1 / MPEG2 video parser
+ * Copyright (c) 2000,2001 Fabrice Bellard.
+ * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+#include "parser.h"
+#include "mpegvideo.h"
+
+static void mpegvideo_extract_headers(AVCodecParserContext *s,
+                                      AVCodecContext *avctx,
+                                      const uint8_t *buf, int buf_size)
+{
+    ParseContext1 *pc = s->priv_data;
+    const uint8_t *buf_end;
+    uint32_t start_code;
+    int frame_rate_index, ext_type, bytes_left;
+    int frame_rate_ext_n, frame_rate_ext_d;
+    int picture_structure, top_field_first, repeat_first_field, progressive_frame;
+    int horiz_size_ext, vert_size_ext, bit_rate_ext;
+//FIXME replace the crap with get_bits()
+    s->repeat_pict = 0;
+    buf_end = buf + buf_size;
+    while (buf < buf_end) {
+        start_code= -1;
+        buf= ff_find_start_code(buf, buf_end, &start_code);
+        bytes_left = buf_end - buf;
+        switch(start_code) {
+        case PICTURE_START_CODE:
+            if (bytes_left >= 2) {
+                s->pict_type = (buf[1] >> 3) & 7;
+            }
+            break;
+        case SEQ_START_CODE:
+            if (bytes_left >= 7) {
+                pc->width  = (buf[0] << 4) | (buf[1] >> 4);
+                pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
+                avcodec_set_dimensions(avctx, pc->width, pc->height);
+                frame_rate_index = buf[3] & 0xf;
+                pc->frame_rate.den = avctx->time_base.den = ff_frame_rate_tab[frame_rate_index].num;
+                pc->frame_rate.num = avctx->time_base.num = ff_frame_rate_tab[frame_rate_index].den;
+                avctx->bit_rate = ((buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6))*400;
+                avctx->codec_id = CODEC_ID_MPEG1VIDEO;
+                avctx->sub_id = 1;
+            }
+            break;
+        case EXT_START_CODE:
+            if (bytes_left >= 1) {
+                ext_type = (buf[0] >> 4);
+                switch(ext_type) {
+                case 0x1: /* sequence extension */
+                    if (bytes_left >= 6) {
+                        horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
+                        vert_size_ext = (buf[2] >> 5) & 3;
+                        bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
+                        frame_rate_ext_n = (buf[5] >> 5) & 3;
+                        frame_rate_ext_d = (buf[5] & 0x1f);
+                        pc->progressive_sequence = buf[1] & (1 << 3);
+                        avctx->has_b_frames= !(buf[5] >> 7);
+
+                        pc->width  |=(horiz_size_ext << 12);
+                        pc->height |=( vert_size_ext << 12);
+                        avctx->bit_rate += (bit_rate_ext << 18) * 400;
+                        avcodec_set_dimensions(avctx, pc->width, pc->height);
+                        avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1);
+                        avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1);
+                        avctx->codec_id = CODEC_ID_MPEG2VIDEO;
+                        avctx->sub_id = 2; /* forces MPEG2 */
+                    }
+                    break;
+                case 0x8: /* picture coding extension */
+                    if (bytes_left >= 5) {
+                        picture_structure = buf[2]&3;
+                        top_field_first = buf[3] & (1 << 7);
+                        repeat_first_field = buf[3] & (1 << 1);
+                        progressive_frame = buf[4] & (1 << 7);
+
+                        /* check if we must repeat the frame */
+                        if (repeat_first_field) {
+                            if (pc->progressive_sequence) {
+                                if (top_field_first)
+                                    s->repeat_pict = 4;
+                                else
+                                    s->repeat_pict = 2;
+                            } else if (progressive_frame) {
+                                s->repeat_pict = 1;
+                            }
+                        }
+
+                        /* the packet only represents half a frame
+                           XXX,FIXME maybe find a different solution */
+                        if(picture_structure != 3)
+                            s->repeat_pict = -1;
+                    }
+                    break;
+                }
+            }
+            break;
+        case -1:
+            goto the_end;
+        default:
+            /* we stop parsing when we encounter a slice. It ensures
+               that this function takes a negligible amount of time */
+            if (start_code >= SLICE_MIN_START_CODE &&
+                start_code <= SLICE_MAX_START_CODE)
+                goto the_end;
+            break;
+        }
+    }
+ the_end: ;
+}
+
+static int mpegvideo_parse(AVCodecParserContext *s,
+                           AVCodecContext *avctx,
+                           uint8_t **poutbuf, int *poutbuf_size,
+                           const uint8_t *buf, int buf_size)
+{
+    ParseContext1 *pc1 = s->priv_data;
+    ParseContext *pc= &pc1->pc;
+    int next;
+
+    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
+        next= buf_size;
+    }else{
+        next= mpeg1_find_frame_end(pc, buf, buf_size);
+
+        if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
+            *poutbuf = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+
+    }
+    /* we have a full frame : we just parse the first few MPEG headers
+       to have the full timing information. The time take by this
+       function should be negligible for uncorrupted streams */
+    mpegvideo_extract_headers(s, avctx, buf, buf_size);
+#if 0
+    printf("pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
+           s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict);
+#endif
+
+    *poutbuf = (uint8_t *)buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+static int mpegvideo_split(AVCodecContext *avctx,
+                           const uint8_t *buf, int buf_size)
+{
+    int i;
+    uint32_t state= -1;
+
+    for(i=0; i<buf_size; i++){
+        state= (state<<8) | buf[i];
+        if(state != 0x1B3 && state != 0x1B5 && state < 0x200 && state >= 0x100)
+            return i-3;
+    }
+    return 0;
+}
+
+AVCodecParser mpegvideo_parser = {
+    { CODEC_ID_MPEG1VIDEO, CODEC_ID_MPEG2VIDEO },
+    sizeof(ParseContext1),
+    NULL,
+    mpegvideo_parse,
+    ff_parse1_close,
+    mpegvideo_split,
+};