ffmpeg-2.8.5

git-svn-id: svn://kolibrios.org@6147 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/ffmpeg/ffmpeg-2.8/libavcodec/mpeg4video_parser.c

@@ -0,0 +1,161 @@
+/*
+ * MPEG4 Video frame extraction
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * 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
+ */
+
+#define UNCHECKED_BITSTREAM_READER 1
+
+#include "internal.h"
+#include "parser.h"
+#include "mpegvideo.h"
+#include "mpeg4video.h"
+#include "mpeg4video_parser.h"
+
+struct Mp4vParseContext {
+    ParseContext pc;
+    Mpeg4DecContext dec_ctx;
+    int first_picture;
+};
+
+int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
+{
+    int vop_found, i;
+    uint32_t state;
+
+    vop_found = pc->frame_start_found;
+    state     = pc->state;
+
+    i = 0;
+    if (!vop_found) {
+        for (i = 0; i < buf_size; i++) {
+            state = (state << 8) | buf[i];
+            if (state == 0x1B6) {
+                i++;
+                vop_found = 1;
+                break;
+            }
+        }
+    }
+
+    if (vop_found) {
+        /* EOF considered as end of frame */
+        if (buf_size == 0)
+            return 0;
+        for (; i < buf_size; i++) {
+            state = (state << 8) | buf[i];
+            if ((state & 0xFFFFFF00) == 0x100) {
+                pc->frame_start_found = 0;
+                pc->state             = -1;
+                return i - 3;
+            }
+        }
+    }
+    pc->frame_start_found = vop_found;
+    pc->state             = state;
+    return END_NOT_FOUND;
+}
+
+/* XXX: make it use less memory */
+static int mpeg4_decode_header(AVCodecParserContext *s1, AVCodecContext *avctx,
+                               const uint8_t *buf, int buf_size)
+{
+    struct Mp4vParseContext *pc = s1->priv_data;
+    Mpeg4DecContext *dec_ctx = &pc->dec_ctx;
+    MpegEncContext *s = &dec_ctx->m;
+    GetBitContext gb1, *gb = &gb1;
+    int ret;
+
+    s->avctx               = avctx;
+    s->current_picture_ptr = &s->current_picture;
+
+    if (avctx->extradata_size && pc->first_picture) {
+        init_get_bits(gb, avctx->extradata, avctx->extradata_size * 8);
+        ret = ff_mpeg4_decode_picture_header(dec_ctx, gb);
+        if (ret < -1)
+            av_log(avctx, AV_LOG_WARNING, "Failed to parse extradata\n");
+    }
+
+    init_get_bits(gb, buf, 8 * buf_size);
+    ret = ff_mpeg4_decode_picture_header(dec_ctx, gb);
+    if (s->width && (!avctx->width || !avctx->height ||
+                     !avctx->coded_width || !avctx->coded_height)) {
+        ret = ff_set_dimensions(avctx, s->width, s->height);
+        if (ret < 0)
+            return ret;
+    }
+    if((s1->flags & PARSER_FLAG_USE_CODEC_TS) && s->avctx->time_base.den>0 && ret>=0){
+        av_assert1(s1->pts == AV_NOPTS_VALUE);
+        av_assert1(s1->dts == AV_NOPTS_VALUE);
+
+        s1->pts = av_rescale_q(s->time, (AVRational){1, s->avctx->time_base.den}, (AVRational){1, 1200000});
+    }
+
+    s1->pict_type     = s->pict_type;
+    pc->first_picture = 0;
+    return ret;
+}
+
+static av_cold int mpeg4video_parse_init(AVCodecParserContext *s)
+{
+    struct Mp4vParseContext *pc = s->priv_data;
+
+    ff_mpeg4videodec_static_init();
+
+    pc->first_picture           = 1;
+    pc->dec_ctx.m.quant_precision     = 5;
+    pc->dec_ctx.m.slice_context_count = 1;
+    pc->dec_ctx.showed_packed_warning = 1;
+    return 0;
+}
+
+static int mpeg4video_parse(AVCodecParserContext *s,
+                            AVCodecContext *avctx,
+                            const uint8_t **poutbuf, int *poutbuf_size,
+                            const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+    int next;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
+        next = buf_size;
+    } else {
+        next = ff_mpeg4_find_frame_end(pc, buf, buf_size);
+
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf      = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+    mpeg4_decode_header(s, avctx, buf, buf_size);
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+AVCodecParser ff_mpeg4video_parser = {
+    .codec_ids      = { AV_CODEC_ID_MPEG4 },
+    .priv_data_size = sizeof(struct Mp4vParseContext),
+    .parser_init    = mpeg4video_parse_init,
+    .parser_parse   = mpeg4video_parse,
+    .parser_close   = ff_parse_close,
+    .split          = ff_mpeg4video_split,
+};