Head

GCC Code Coverage Report

Directory:	../../../ffmpeg/		Exec	Total	Coverage
File:	src/libavcodec/mpeg4_unpack_bframes_bsf.c	Lines:	63	70	90.0 %
Date:	2019-11-22 03:34:36	Branches:	40	50	80.0 %


/*
 * Bitstream filter for unpacking DivX-style packed B-frames in MPEG-4 (divx_packed)
 * Copyright (c) 2015 Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
 *
 * 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 "avcodec.h"
#include "bsf.h"
#include "internal.h"
#include "mpeg4video.h"

typedef struct UnpackBFramesBSFContext {
    AVBufferRef *b_frame_ref;
} UnpackBFramesBSFContext;

/* determine the position of the packed marker in the userdata,
 * the number of VOPs and the position of the second VOP */
static void scan_buffer(const uint8_t *buf, int buf_size,
                        int *pos_p, int *nb_vop, int *pos_vop2) {
    uint32_t startcode;
    const uint8_t *end = buf + buf_size, *pos = buf;

    while (pos < end) {
        startcode = -1;
        pos = avpriv_find_start_code(pos, end, &startcode);

        if (startcode == USER_DATA_STARTCODE && pos_p) {
            /* check if the (DivX) userdata string ends with 'p' (packed) */
            for (int i = 0; i < 255 && pos + i + 1 < end; i++) {
                if (pos[i] == 'p' && pos[i + 1] == '\0') {
                    *pos_p = pos + i - buf;
                    break;
                }
            }
        } else if (startcode == VOP_STARTCODE && nb_vop) {
            *nb_vop += 1;
            if (*nb_vop == 2 && pos_vop2) {
                *pos_vop2 = pos - buf - 4; /* subtract 4 bytes startcode */
            }
        }
    }
}

static int mpeg4_unpack_bframes_filter(AVBSFContext *ctx, AVPacket *pkt)
{
    UnpackBFramesBSFContext *s = ctx->priv_data;
    int pos_p = -1, nb_vop = 0, pos_vop2 = -1, ret = 0;

    ret = ff_bsf_get_packet_ref(ctx, pkt);
    if (ret < 0)
        return ret;

    scan_buffer(pkt->data, pkt->size, &pos_p, &nb_vop, &pos_vop2);
    av_log(ctx, AV_LOG_DEBUG, "Found %d VOP startcode(s) in this packet.\n", nb_vop);

    if (pos_vop2 >= 0) {
        if (s->b_frame_ref) {
            av_log(ctx, AV_LOG_WARNING,
                   "Missing one N-VOP packet, discarding one B-frame.\n");
            av_buffer_unref(&s->b_frame_ref);
        }
        /* store a reference to the packed B-frame's data in the BSFContext */
        s->b_frame_ref = av_buffer_ref(pkt->buf);
        if (!s->b_frame_ref) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        s->b_frame_ref->data = pkt->data + pos_vop2;
        s->b_frame_ref->size = pkt->size - pos_vop2;
    }

    if (nb_vop > 2) {
        av_log(ctx, AV_LOG_WARNING,
       "Found %d VOP headers in one packet, only unpacking one.\n", nb_vop);
    }

    if (nb_vop == 1 && s->b_frame_ref) {
        AVBufferRef *tmp = pkt->buf;

        /* make tmp accurately reflect the packet's data */
        tmp->data = pkt->data;
        tmp->size = pkt->size;

        /* replace data in packet with stored data */
        pkt->buf  = s->b_frame_ref;
        pkt->data = s->b_frame_ref->data;
        pkt->size = s->b_frame_ref->size;

        /* store reference to data into BSFContext */
        s->b_frame_ref = tmp;

        if (s->b_frame_ref->size <= MAX_NVOP_SIZE) {
            /* N-VOP - discard stored data */
            av_log(ctx, AV_LOG_DEBUG, "Skipping N-VOP.\n");
            av_buffer_unref(&s->b_frame_ref);
        }
    } else if (nb_vop >= 2) {
        /* use first frame of the packet */
        pkt->size = pos_vop2;
    } else if (pos_p >= 0) {
        ret = av_packet_make_writable(pkt);
        if (ret < 0)
            goto fail;
        av_log(ctx, AV_LOG_DEBUG, "Updating DivX userdata (remove trailing 'p').\n");
        /* remove 'p' (packed) from the end of the (DivX) userdata string */
        pkt->data[pos_p] = '\0';
    } else {
        /* use packet as is */
    }

fail:
    if (ret < 0)
        av_packet_unref(pkt);

    return ret;
}

static int mpeg4_unpack_bframes_init(AVBSFContext *ctx)
{
    if (ctx->par_in->extradata) {
        int pos_p_ext = -1;
        scan_buffer(ctx->par_in->extradata, ctx->par_in->extradata_size, &pos_p_ext, NULL, NULL);
        if (pos_p_ext >= 0) {
            av_log(ctx, AV_LOG_DEBUG,
                   "Updating DivX userdata (remove trailing 'p') in extradata.\n");
            ctx->par_out->extradata[pos_p_ext] = '\0';
        }
    }

    return 0;
}

static void mpeg4_unpack_bframes_close_flush(AVBSFContext *bsfc)
{
    UnpackBFramesBSFContext *ctx = bsfc->priv_data;
    av_buffer_unref(&ctx->b_frame_ref);
}

static const enum AVCodecID codec_ids[] = {
    AV_CODEC_ID_MPEG4, AV_CODEC_ID_NONE,
};

const AVBitStreamFilter ff_mpeg4_unpack_bframes_bsf = {
    .name           = "mpeg4_unpack_bframes",
    .priv_data_size = sizeof(UnpackBFramesBSFContext),
    .init           = mpeg4_unpack_bframes_init,
    .filter         = mpeg4_unpack_bframes_filter,
    .flush          = mpeg4_unpack_bframes_close_flush,
    .close          = mpeg4_unpack_bframes_close_flush,
    .codec_ids      = codec_ids,
};


Generated by: GCOVR (Version 4.1)

Line	Branch	Exec	Source
1			/*
2			* Bitstream filter for unpacking DivX-style packed B-frames in MPEG-4 (divx_packed)
3			* Copyright (c) 2015 Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
4			*
5			* This file is part of FFmpeg.
6			*
7			* FFmpeg is free software; you can redistribute it and/or
8			* modify it under the terms of the GNU Lesser General Public
9			* License as published by the Free Software Foundation; either
10			* version 2.1 of the License, or (at your option) any later version.
11			*
12			* FFmpeg is distributed in the hope that it will be useful,
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15			* Lesser General Public License for more details.
16			*
17			* You should have received a copy of the GNU Lesser General Public
18			* License along with FFmpeg; if not, write to the Free Software
19			* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20			*/
21
22			#include "avcodec.h"
23			#include "bsf.h"
24			#include "internal.h"
25			#include "mpeg4video.h"
26
27			typedef struct UnpackBFramesBSFContext {
28			AVBufferRef *b_frame_ref;
29			} UnpackBFramesBSFContext;
30
31			/* determine the position of the packed marker in the userdata,
32			* the number of VOPs and the position of the second VOP */
33		16	static void scan_buffer(const uint8_t *buf, int buf_size,
34			int pos_p, int nb_vop, int *pos_vop2) {
35			uint32_t startcode;
36		16	const uint8_t end = buf + buf_size, pos = buf;
37
38	✓✓	64	while (pos < end) {
39		48	startcode = -1;
40		48	pos = avpriv_find_start_code(pos, end, &startcode);
41
42	✓✓✓✗	48	if (startcode == USER_DATA_STARTCODE && pos_p) {
43			/* check if the (DivX) userdata string ends with 'p' (packed) */
44	✓✓✓✓	290	for (int i = 0; i < 255 && pos + i + 1 < end; i++) {
45	✓✓✓✓	286	if (pos[i] == 'p' && pos[i + 1] == '\0') {
46		2	*pos_p = pos + i - buf;
47		2	break;
48			}
49			}
50	✓✓✓✗	44	} else if (startcode == VOP_STARTCODE && nb_vop) {
51		20	*nb_vop += 1;
52	✓✓✓✗	20	if (*nb_vop == 2 && pos_vop2) {
53		5	pos_vop2 = pos - buf - 4; / subtract 4 bytes startcode */
54			}
55			}
56			}
57		16	}
58
59		30	static int mpeg4_unpack_bframes_filter(AVBSFContext ctx, AVPacket pkt)
60			{
61		30	UnpackBFramesBSFContext *s = ctx->priv_data;
62		30	int pos_p = -1, nb_vop = 0, pos_vop2 = -1, ret = 0;
63
64		30	ret = ff_bsf_get_packet_ref(ctx, pkt);
65	✓✓	30	if (ret < 0)
66		15	return ret;
67
68		15	scan_buffer(pkt->data, pkt->size, &pos_p, &nb_vop, &pos_vop2);
69		15	av_log(ctx, AV_LOG_DEBUG, "Found %d VOP startcode(s) in this packet.\n", nb_vop);
70
71	✓✓	15	if (pos_vop2 >= 0) {
72	✗✓	5	if (s->b_frame_ref) {
73			av_log(ctx, AV_LOG_WARNING,
74			"Missing one N-VOP packet, discarding one B-frame.\n");
75			av_buffer_unref(&s->b_frame_ref);
76			}
77			/* store a reference to the packed B-frame's data in the BSFContext */
78		5	s->b_frame_ref = av_buffer_ref(pkt->buf);
79	✗✓	5	if (!s->b_frame_ref) {
80			ret = AVERROR(ENOMEM);
81			goto fail;
82			}
83		5	s->b_frame_ref->data = pkt->data + pos_vop2;
84		5	s->b_frame_ref->size = pkt->size - pos_vop2;
85			}
86
87	✗✓	15	if (nb_vop > 2) {
88			av_log(ctx, AV_LOG_WARNING,
89			"Found %d VOP headers in one packet, only unpacking one.\n", nb_vop);
90			}
91
92	✓✓✓✓	22	if (nb_vop == 1 && s->b_frame_ref) {
93		7	AVBufferRef *tmp = pkt->buf;
94
95			/* make tmp accurately reflect the packet's data */
96		7	tmp->data = pkt->data;
97		7	tmp->size = pkt->size;
98
99			/* replace data in packet with stored data */
100		7	pkt->buf = s->b_frame_ref;
101		7	pkt->data = s->b_frame_ref->data;
102		7	pkt->size = s->b_frame_ref->size;
103
104			/* store reference to data into BSFContext */
105		7	s->b_frame_ref = tmp;
106
107	✓✓	7	if (s->b_frame_ref->size <= MAX_NVOP_SIZE) {
108			/* N-VOP - discard stored data */
109		4	av_log(ctx, AV_LOG_DEBUG, "Skipping N-VOP.\n");
110		4	av_buffer_unref(&s->b_frame_ref);
111			}
112	✓✓	8	} else if (nb_vop >= 2) {
113			/* use first frame of the packet */
114		5	pkt->size = pos_vop2;
115	✓✓	3	} else if (pos_p >= 0) {
116		1	ret = av_packet_make_writable(pkt);
117	✗✓	1	if (ret < 0)
118			goto fail;
119		1	av_log(ctx, AV_LOG_DEBUG, "Updating DivX userdata (remove trailing 'p').\n");
120			/* remove 'p' (packed) from the end of the (DivX) userdata string */
121		1	pkt->data[pos_p] = '\0';
122			} else {
123			/* use packet as is */
124			}
125
126		2	fail:
127	✗✓	15	if (ret < 0)
128			av_packet_unref(pkt);
129
130		15	return ret;
131			}
132
133		1	static int mpeg4_unpack_bframes_init(AVBSFContext *ctx)
134			{
135	✓✗	1	if (ctx->par_in->extradata) {
136		1	int pos_p_ext = -1;
137		1	scan_buffer(ctx->par_in->extradata, ctx->par_in->extradata_size, &pos_p_ext, NULL, NULL);
138	✓✗	1	if (pos_p_ext >= 0) {
139		1	av_log(ctx, AV_LOG_DEBUG,
140			"Updating DivX userdata (remove trailing 'p') in extradata.\n");
141		1	ctx->par_out->extradata[pos_p_ext] = '\0';
142			}
143			}
144
145		1	return 0;
146			}
147
148		1	static void mpeg4_unpack_bframes_close_flush(AVBSFContext *bsfc)
149			{
150		1	UnpackBFramesBSFContext *ctx = bsfc->priv_data;
151		1	av_buffer_unref(&ctx->b_frame_ref);
152		1	}
153
154			static const enum AVCodecID codec_ids[] = {
155			AV_CODEC_ID_MPEG4, AV_CODEC_ID_NONE,
156			};
157
158			const AVBitStreamFilter ff_mpeg4_unpack_bframes_bsf = {
159			.name = "mpeg4_unpack_bframes",
160			.priv_data_size = sizeof(UnpackBFramesBSFContext),
161			.init = mpeg4_unpack_bframes_init,
162			.filter = mpeg4_unpack_bframes_filter,
163			.flush = mpeg4_unpack_bframes_close_flush,
164			.close = mpeg4_unpack_bframes_close_flush,
165			.codec_ids = codec_ids,
166			};