| /* |
| * MPEG-1 / MPEG-2 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 "libavutil/avassert.h" |
| #include "decode.h" |
| #include "parser.h" |
| #include "mpeg12.h" |
| #include "mpeg12data.h" |
| #include "startcode.h" |
| |
| struct MpvParseContext { |
| ParseContext pc; |
| AVRational frame_rate; |
| int progressive_sequence; |
| int width, height; |
| }; |
| |
| /** |
| * Find the end of the current frame in the bitstream. |
| * @return the position of the first byte of the next frame, or -1 |
| */ |
| static int mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, |
| int buf_size, AVCodecParserContext *s) |
| { |
| int i; |
| uint32_t state = pc->state; |
| |
| /* EOF considered as end of frame */ |
| if (buf_size == 0) |
| return 0; |
| |
| /* |
| 0 frame start -> 1/4 |
| 1 first_SEQEXT -> 0/2 |
| 2 first field start -> 3/0 |
| 3 second_SEQEXT -> 2/0 |
| 4 searching end |
| */ |
| |
| for (i = 0; i < buf_size; i++) { |
| av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4); |
| if (pc->frame_start_found & 1) { |
| if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80) |
| pc->frame_start_found--; |
| else if (state == EXT_START_CODE + 2) { |
| if ((buf[i] & 3) == 3) |
| pc->frame_start_found = 0; |
| else |
| pc->frame_start_found = (pc->frame_start_found + 1) & 3; |
| } |
| state++; |
| } else { |
| i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1; |
| if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) { |
| i++; |
| pc->frame_start_found = 4; |
| } |
| if (state == SEQ_END_CODE) { |
| pc->frame_start_found = 0; |
| pc->state = -1; |
| return i + 1; |
| } |
| if (pc->frame_start_found == 2 && state == SEQ_START_CODE) |
| pc->frame_start_found = 0; |
| if (pc->frame_start_found < 4 && state == EXT_START_CODE) |
| pc->frame_start_found++; |
| if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) { |
| if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) { |
| pc->frame_start_found = 0; |
| pc->state = -1; |
| return i - 3; |
| } |
| } |
| if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) { |
| ff_fetch_timestamp(s, i - 3, 1, i > 3); |
| } |
| } |
| } |
| pc->state = state; |
| return END_NOT_FOUND; |
| } |
| |
| static void mpegvideo_extract_headers(AVCodecParserContext *s, |
| AVCodecContext *avctx, |
| const uint8_t *buf, int buf_size) |
| { |
| struct MpvParseContext *pc = s->priv_data; |
| const uint8_t *buf_end = buf + buf_size; |
| int bytes_left; |
| int did_set_size=0; |
| int set_dim_ret = 0; |
| int bit_rate = 0; |
| int vbv_delay = 0; |
| enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE; |
| |
| // number of picture coding extensions (i.e. MPEG2 pictures) |
| // in this packet - should be 1 or 2 |
| int nb_pic_ext = 0; |
| // when there are two pictures in the packet this indicates |
| // which field is in the first of them |
| int first_field = AV_FIELD_UNKNOWN; |
| |
| //FIXME replace the crap with get_bits() |
| while (buf < buf_end) { |
| uint32_t start_code = -1; |
| buf= avpriv_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; |
| if (bytes_left >= 4) |
| vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3] >> 3); |
| } |
| break; |
| case SEQ_START_CODE: |
| if (bytes_left >= 7) { |
| int frame_rate_index; |
| |
| pc->width = (buf[0] << 4) | (buf[1] >> 4); |
| pc->height = ((buf[1] & 0x0f) << 8) | buf[2]; |
| if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){ |
| set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height); |
| did_set_size=1; |
| } |
| pix_fmt = AV_PIX_FMT_YUV420P; |
| frame_rate_index = buf[3] & 0xf; |
| pc->frame_rate = avctx->framerate = ff_mpeg12_frame_rate_tab[frame_rate_index]; |
| bit_rate = (buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6); |
| avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO; |
| #if FF_API_TICKS_PER_FRAME |
| FF_DISABLE_DEPRECATION_WARNINGS |
| avctx->ticks_per_frame = 1; |
| FF_ENABLE_DEPRECATION_WARNINGS |
| #endif |
| } |
| break; |
| case EXT_START_CODE: |
| if (bytes_left >= 1) { |
| switch (buf[0] >> 4) { // ext_type |
| case 0x1: /* sequence extension */ |
| if (bytes_left >= 6) { |
| int horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7); |
| int vert_size_ext = (buf[2] >> 5) & 3; |
| int bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1); |
| int frame_rate_ext_n = (buf[5] >> 5) & 3; |
| int frame_rate_ext_d = (buf[5] & 0x1f); |
| pc->progressive_sequence = buf[1] & (1 << 3); |
| avctx->has_b_frames= !(buf[5] >> 7); |
| |
| switch ((buf[1] >> 1) & 3) { // chroma_format |
| case 1: pix_fmt = AV_PIX_FMT_YUV420P; break; |
| case 2: pix_fmt = AV_PIX_FMT_YUV422P; break; |
| case 3: pix_fmt = AV_PIX_FMT_YUV444P; break; |
| } |
| |
| pc->width = (pc->width & 0xFFF) | (horiz_size_ext << 12); |
| pc->height = (pc->height& 0xFFF) | ( vert_size_ext << 12); |
| bit_rate = (bit_rate&0x3FFFF) | (bit_rate_ext << 18); |
| if(did_set_size) |
| set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height); |
| avctx->framerate.num = pc->frame_rate.num * (frame_rate_ext_n + 1); |
| avctx->framerate.den = pc->frame_rate.den * (frame_rate_ext_d + 1); |
| avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO; |
| #if FF_API_TICKS_PER_FRAME |
| FF_DISABLE_DEPRECATION_WARNINGS |
| avctx->ticks_per_frame = 2; |
| FF_ENABLE_DEPRECATION_WARNINGS |
| #endif |
| } |
| break; |
| case 0x8: /* picture coding extension */ |
| if (bytes_left >= 5) { |
| int top_field_first = buf[3] & (1 << 7); |
| int repeat_first_field = buf[3] & (1 << 1); |
| int progressive_frame = buf[4] & (1 << 7); |
| |
| /* check if we must repeat the frame */ |
| s->repeat_pict = 1; |
| if (repeat_first_field) { |
| if (pc->progressive_sequence) { |
| if (top_field_first) |
| s->repeat_pict = 5; |
| else |
| s->repeat_pict = 3; |
| } else if (progressive_frame) { |
| s->repeat_pict = 2; |
| } |
| } |
| |
| if (!pc->progressive_sequence && !progressive_frame) { |
| if (top_field_first) |
| s->field_order = AV_FIELD_TT; |
| else |
| s->field_order = AV_FIELD_BB; |
| } else |
| s->field_order = AV_FIELD_PROGRESSIVE; |
| |
| s->picture_structure = buf[2] & 3; |
| |
| if (!nb_pic_ext) { |
| // remember parity of the first field for the case |
| // when there are 2 fields in packet |
| switch (s->picture_structure) { |
| case AV_PICTURE_STRUCTURE_BOTTOM_FIELD: first_field = AV_FIELD_BB; break; |
| case AV_PICTURE_STRUCTURE_TOP_FIELD: first_field = AV_FIELD_TT; break; |
| } |
| } |
| |
| nb_pic_ext++; |
| } |
| 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: |
| if (set_dim_ret < 0) |
| av_log(avctx, AV_LOG_ERROR, "Failed to set dimensions\n"); |
| |
| if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && bit_rate && bit_rate != 0x3FFFF) { |
| avctx->rc_max_rate = 400LL*bit_rate; |
| } |
| if (bit_rate && |
| ((avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && bit_rate != 0x3FFFF) || vbv_delay != 0xFFFF)) { |
| avctx->bit_rate = 400LL*bit_rate; |
| } |
| |
| if (pix_fmt != AV_PIX_FMT_NONE) { |
| s->format = pix_fmt; |
| s->width = pc->width; |
| s->height = pc->height; |
| s->coded_width = FFALIGN(pc->width, 16); |
| s->coded_height = FFALIGN(pc->height, 16); |
| } |
| |
| if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO || nb_pic_ext > 1) { |
| s->repeat_pict = 1; |
| s->picture_structure = AV_PICTURE_STRUCTURE_FRAME; |
| s->field_order = nb_pic_ext > 1 ? first_field : AV_FIELD_PROGRESSIVE; |
| } |
| } |
| |
| static int mpegvideo_parse(AVCodecParserContext *s, |
| AVCodecContext *avctx, |
| const uint8_t **poutbuf, int *poutbuf_size, |
| const uint8_t *buf, int buf_size) |
| { |
| struct MpvParseContext *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, s); |
| |
| if (ff_combine_frame(pc, next, &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); |
| ff_dlog(NULL, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n", |
| s->pict_type, av_q2d(avctx->framerate), s->repeat_pict); |
| |
| *poutbuf = buf; |
| *poutbuf_size = buf_size; |
| return next; |
| } |
| |
| static int mpegvideo_parse_init(AVCodecParserContext *s) |
| { |
| s->pict_type = AV_PICTURE_TYPE_NONE; // first frame might be partial |
| return 0; |
| } |
| |
| const AVCodecParser ff_mpegvideo_parser = { |
| .codec_ids = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO }, |
| .priv_data_size = sizeof(struct MpvParseContext), |
| .parser_init = mpegvideo_parse_init, |
| .parser_parse = mpegvideo_parse, |
| .parser_close = ff_parse_close, |
| }; |
