/src/ffmpeg/libavformat/mxg.c

Source (jump to first uncovered line)
/*
 * MxPEG clip file demuxer
 * Copyright (c) 2010 Anatoly Nenashev
 *
 * 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/channel_layout.h"
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "libavcodec/mjpeg.h"
#include "avformat.h"
#include "demux.h"
#include "internal.h"
#include "avio.h"

#define DEFAULT_PACKET_SIZE 1024
#define OVERREAD_SIZE 3

typedef struct MXGContext {
    uint8_t *buffer;
    uint8_t *buffer_ptr;
    uint8_t *soi_ptr;
    unsigned int buffer_size;
    int64_t dts;
    unsigned int cache_size;
} MXGContext;

static int mxg_read_header(AVFormatContext *s)
{
    AVStream *video_st, *audio_st;
    MXGContext *mxg = s->priv_data;

    /* video parameters will be extracted from the compressed bitstream */
    video_st = avformat_new_stream(s, NULL);
    if (!video_st)
        return AVERROR(ENOMEM);
    video_st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    video_st->codecpar->codec_id = AV_CODEC_ID_MXPEG;
    avpriv_set_pts_info(video_st, 64, 1, 1000000);

    audio_st = avformat_new_stream(s, NULL);
    if (!audio_st)
        return AVERROR(ENOMEM);
    audio_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
    audio_st->codecpar->codec_id = AV_CODEC_ID_PCM_ALAW;
    audio_st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
    audio_st->codecpar->sample_rate = 8000;
    audio_st->codecpar->bits_per_coded_sample = 8;
    audio_st->codecpar->block_align = 1;
    avpriv_set_pts_info(audio_st, 64, 1, 1000000);

    mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0;
    mxg->buffer_size = 0;
    mxg->dts = AV_NOPTS_VALUE;
    mxg->cache_size = 0;

    return 0;
}

static uint8_t* mxg_find_startmarker(uint8_t *p, uint8_t *end)
{
    for (; p < end - 3; p += 4) {
        uint32_t x = AV_RN32(p);

        if (x & (~(x+0x01010101)) & 0x80808080) {
            if (p[0] == 0xff) {
                return p;
            } else if (p[1] == 0xff) {
                return p+1;
            } else if (p[2] == 0xff) {
                return p+2;
            } else if (p[3] == 0xff) {
                return p+3;
            }
        }
    }

    for (; p < end; ++p) {
        if (*p == 0xff) return p;
    }

    return end;
}

static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size)
{
    MXGContext *mxg = s->priv_data;
    unsigned int current_pos = mxg->buffer_ptr - mxg->buffer;
    unsigned int soi_pos;
    uint8_t *buffer;
    int ret;

    /* reallocate internal buffer */
    if (current_pos > current_pos + cache_size)
        return AVERROR(ENOMEM);
    soi_pos = mxg->soi_ptr - mxg->buffer;
    buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
                             current_pos + cache_size +
                             AV_INPUT_BUFFER_PADDING_SIZE);
    if (!buffer)
        return AVERROR(ENOMEM);
    mxg->buffer = buffer;
    mxg->buffer_ptr = mxg->buffer + current_pos;
    if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos;

    /* get data */
    ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size,
                     cache_size - mxg->cache_size);
    if (ret < 0)
        return ret;

    mxg->cache_size += ret;

    memset(mxg->buffer_ptr + mxg->cache_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);

    return ret;
}

static int mxg_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int ret;
    unsigned int size;
    uint8_t *startmarker_ptr, *end, *search_end, marker;
    MXGContext *mxg = s->priv_data;

    while (!avio_feof(s->pb) && !s->pb->error){
        if (mxg->cache_size <= OVERREAD_SIZE) {
            /* update internal buffer */
            ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE);
            if (ret < 0)
                return ret;
        }
        end = mxg->buffer_ptr + mxg->cache_size;

        /* find start marker - 0xff */
        if (mxg->cache_size > OVERREAD_SIZE) {
            search_end = end - OVERREAD_SIZE;
            startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
        } else {
            search_end = end;
            startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
            if (startmarker_ptr >= search_end - 1 ||
                *(startmarker_ptr + 1) != EOI) break;
        }

        if (startmarker_ptr != search_end) { /* start marker found */
            marker = *(startmarker_ptr + 1);
            mxg->buffer_ptr = startmarker_ptr + 2;
            mxg->cache_size = end - mxg->buffer_ptr;

            if (marker == SOI) {
                mxg->soi_ptr = startmarker_ptr;
            } else if (marker == EOI) {
                if (!mxg->soi_ptr) {
                    av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n");
                    continue;
                }

                size = mxg->buffer_ptr - mxg->soi_ptr;
                ret = av_new_packet(pkt, size);
                if (ret < 0)
                    return ret;
                memcpy(pkt->data, mxg->soi_ptr, size);

                pkt->pts = pkt->dts = mxg->dts;
                pkt->stream_index = 0;

                if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) {
                    if (mxg->cache_size > 0) {
                        memmove(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
                    }

                    mxg->buffer_ptr = mxg->buffer;
                }
                mxg->soi_ptr = 0;

                return pkt->size;
            } else if ( (SOF0 <= marker && marker <= SOF15) ||
                        (SOS  <= marker && marker <= COM) ) {
                /* all other markers that start marker segment also contain
                   length value (see specification for JPEG Annex B.1) */
                size = AV_RB16(mxg->buffer_ptr);
                if (size < 2)
                    return AVERROR(EINVAL);

                if (mxg->cache_size < size) {
                    ret = mxg_update_cache(s, size);
                    if (ret < 0)
                        return ret;
                    startmarker_ptr = mxg->buffer_ptr - 2;
                    mxg->cache_size = 0;
                } else {
                    mxg->cache_size -= size;
                }

                mxg->buffer_ptr += size;

                if (marker == APP13 && size >= 16) { /* audio data */
                    ret = av_new_packet(pkt, size - 14);
                    if (ret < 0)
                        return ret;
                    memcpy(pkt->data, startmarker_ptr + 16, size - 14);

                    /* time (GMT) of first sample in usec since 1970, little-endian */
                    pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
                    pkt->stream_index = 1;

                    if (startmarker_ptr - mxg->buffer > mxg->cache_size) {
                        if (mxg->cache_size > 0) {
                            memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
                        }
                        mxg->buffer_ptr = mxg->buffer;
                    }

                    return pkt->size;
                } else if (marker == COM && size >= 18 &&
                           !strncmp(startmarker_ptr + 4, "MXF", 3)) {
                    /* time (GMT) of video frame in usec since 1970, little-endian */
                    mxg->dts = AV_RL64(startmarker_ptr + 12);
                }
            }
        } else {
            /* start marker not found */
            mxg->buffer_ptr = search_end;
            mxg->cache_size = OVERREAD_SIZE;
        }
    }

    return AVERROR_EOF;
}

static int mxg_close(struct AVFormatContext *s)
{
    MXGContext *mxg = s->priv_data;
    av_freep(&mxg->buffer);
    return 0;
}

const FFInputFormat ff_mxg_demuxer = {
    .p.name         = "mxg",
    .p.long_name    = NULL_IF_CONFIG_SMALL("MxPEG clip"),
    .p.extensions   = "mxg",
    .priv_data_size = sizeof(MXGContext),
    .read_header    = mxg_read_header,
    .read_packet    = mxg_read_packet,
    .read_close     = mxg_close,
};

Coverage Report

Created: 2025-08-28 07:12

Line	Count	Source (jump to first uncovered line)
1		/*
2		* MxPEG clip file demuxer
3		* Copyright (c) 2010 Anatoly Nenashev
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 "libavutil/channel_layout.h"
23		#include "libavutil/internal.h"
24		#include "libavutil/intreadwrite.h"
25		#include "libavutil/mem.h"
26		#include "libavcodec/mjpeg.h"
27		#include "avformat.h"
28		#include "demux.h"
29		#include "internal.h"
30		#include "avio.h"
31
32	37.2k	#define DEFAULT_PACKET_SIZE 1024
33	8.83M	#define OVERREAD_SIZE 3
34
35		typedef struct MXGContext {
36		uint8_t *buffer;
37		uint8_t *buffer_ptr;
38		uint8_t *soi_ptr;
39		unsigned int buffer_size;
40		int64_t dts;
41		unsigned int cache_size;
42		} MXGContext;
43
44		static int mxg_read_header(AVFormatContext *s)
45	7.01k	{
46	7.01k	AVStream video_st, audio_st;
47	7.01k	MXGContext *mxg = s->priv_data;
48
49		/* video parameters will be extracted from the compressed bitstream */
50	7.01k	video_st = avformat_new_stream(s, NULL);
51	7.01k	if (!video_st)
52	0	return AVERROR(ENOMEM);
53	7.01k	video_st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
54	7.01k	video_st->codecpar->codec_id = AV_CODEC_ID_MXPEG;
55	7.01k	avpriv_set_pts_info(video_st, 64, 1, 1000000);
56
57	7.01k	audio_st = avformat_new_stream(s, NULL);
58	7.01k	if (!audio_st)
59	0	return AVERROR(ENOMEM);
60	7.01k	audio_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
61	7.01k	audio_st->codecpar->codec_id = AV_CODEC_ID_PCM_ALAW;
62	7.01k	audio_st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
63	7.01k	audio_st->codecpar->sample_rate = 8000;
64	7.01k	audio_st->codecpar->bits_per_coded_sample = 8;
65	7.01k	audio_st->codecpar->block_align = 1;
66	7.01k	avpriv_set_pts_info(audio_st, 64, 1, 1000000);
67
68	7.01k	mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0;
69	7.01k	mxg->buffer_size = 0;
70	7.01k	mxg->dts = AV_NOPTS_VALUE;
71	7.01k	mxg->cache_size = 0;
72
73	7.01k	return 0;
74	7.01k	}
75
76		static uint8_t* mxg_find_startmarker(uint8_t p, uint8_t end)
77	2.92M	{
78	7.42M	for (; p < end - 3; p += 4) {
79	7.40M	uint32_t x = AV_RN32(p);
80
81	7.40M	if (x & (~(x+0x01010101)) & 0x80808080) {
82	2.89M	if (p[0] == 0xff) {
83	1.37M	return p;
84	1.51M	} else if (p[1] == 0xff) {
85	206k	return p+1;
86	1.31M	} else if (p[2] == 0xff) {
87	1.27M	return p+2;
88	1.27M	} else if (p[3] == 0xff) {
89	37.4k	return p+3;
90	37.4k	}
91	2.89M	}
92	7.40M	}
93
94	41.7k	for (; p < end; ++p) {
95	21.3k	if (*p == 0xff) return p;
96	21.3k	}
97
98	20.3k	return end;
99	26.2k	}
100
101		static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size)
102	41.8k	{
103	41.8k	MXGContext *mxg = s->priv_data;
104	41.8k	unsigned int current_pos = mxg->buffer_ptr - mxg->buffer;
105	41.8k	unsigned int soi_pos;
106	41.8k	uint8_t *buffer;
107	41.8k	int ret;
108
109		/* reallocate internal buffer */
110	41.8k	if (current_pos > current_pos + cache_size)
111	0	return AVERROR(ENOMEM);
112	41.8k	soi_pos = mxg->soi_ptr - mxg->buffer;
113	41.8k	buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
114	41.8k	current_pos + cache_size +
115	41.8k	AV_INPUT_BUFFER_PADDING_SIZE);
116	41.8k	if (!buffer)
117	0	return AVERROR(ENOMEM);
118	41.8k	mxg->buffer = buffer;
119	41.8k	mxg->buffer_ptr = mxg->buffer + current_pos;
120	41.8k	if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos;
121
122		/* get data */
123	41.8k	ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size,
124	41.8k	cache_size - mxg->cache_size);
125	41.8k	if (ret < 0)
126	5.64k	return ret;
127
128	36.1k	mxg->cache_size += ret;
129
130	36.1k	memset(mxg->buffer_ptr + mxg->cache_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
131
132	36.1k	return ret;
133	41.8k	}
134
135		static int mxg_read_packet(AVFormatContext s, AVPacket pkt)
136	1.12M	{
137	1.12M	int ret;
138	1.12M	unsigned int size;
139	1.12M	uint8_t startmarker_ptr, end, *search_end, marker;
140	1.12M	MXGContext *mxg = s->priv_data;
141
142	2.93M	while (!avio_feof(s->pb) && !s->pb->error){
143	2.92M	if (mxg->cache_size <= OVERREAD_SIZE) {
144		/* update internal buffer */
145	37.2k	ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE);
146	37.2k	if (ret < 0)
147	5.23k	return ret;
148	37.2k	}
149	2.92M	end = mxg->buffer_ptr + mxg->cache_size;
150
151		/* find start marker - 0xff */
152	2.92M	if (mxg->cache_size > OVERREAD_SIZE) {
153	2.92M	search_end = end - OVERREAD_SIZE;
154	2.92M	startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
155	2.92M	} else {
156	145	search_end = end;
157	145	startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
158	145	if (startmarker_ptr >= search_end - 1 \|\|
159	145	*(startmarker_ptr + 1) != EOI) break;
160	145	}
161
162	2.92M	if (startmarker_ptr != search_end) { /* start marker found */
163	2.90M	marker = *(startmarker_ptr + 1);
164	2.90M	mxg->buffer_ptr = startmarker_ptr + 2;
165	2.90M	mxg->cache_size = end - mxg->buffer_ptr;
166
167	2.90M	if (marker == SOI) {
168	1.11M	mxg->soi_ptr = startmarker_ptr;
169	1.78M	} else if (marker == EOI) {
170	1.11M	if (!mxg->soi_ptr) {
171	15.5k	av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n");
172	15.5k	continue;
173	15.5k	}
174
175	1.09M	size = mxg->buffer_ptr - mxg->soi_ptr;
176	1.09M	ret = av_new_packet(pkt, size);
177	1.09M	if (ret < 0)
178	78	return ret;
179	1.09M	memcpy(pkt->data, mxg->soi_ptr, size);
180
181	1.09M	pkt->pts = pkt->dts = mxg->dts;
182	1.09M	pkt->stream_index = 0;
183
184	1.09M	if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) {
185	47.7k	if (mxg->cache_size > 0) {
186	47.7k	memmove(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
187	47.7k	}
188
189	47.7k	mxg->buffer_ptr = mxg->buffer;
190	47.7k	}
191	1.09M	mxg->soi_ptr = 0;
192
193	1.09M	return pkt->size;
194	1.09M	} else if ( (SOF0 <= marker && marker <= SOF15) \|\|
195	669k	(SOS <= marker && marker <= COM) ) {
196		/* all other markers that start marker segment also contain
197		length value (see specification for JPEG Annex B.1) */
198	72.6k	size = AV_RB16(mxg->buffer_ptr);
199	72.6k	if (size < 2)
200	138	return AVERROR(EINVAL);
201
202	72.5k	if (mxg->cache_size < size) {
203	4.57k	ret = mxg_update_cache(s, size);
204	4.57k	if (ret < 0)
205	406	return ret;
206	4.16k	startmarker_ptr = mxg->buffer_ptr - 2;
207	4.16k	mxg->cache_size = 0;
208	67.9k	} else {
209	67.9k	mxg->cache_size -= size;
210	67.9k	}
211
212	72.1k	mxg->buffer_ptr += size;
213
214	72.1k	if (marker == APP13 && size >= 16) { /* audio data */
215	13.9k	ret = av_new_packet(pkt, size - 14);
216	13.9k	if (ret < 0)
217	0	return ret;
218	13.9k	memcpy(pkt->data, startmarker_ptr + 16, size - 14);
219
220		/* time (GMT) of first sample in usec since 1970, little-endian */
221	13.9k	pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
222	13.9k	pkt->stream_index = 1;
223
224	13.9k	if (startmarker_ptr - mxg->buffer > mxg->cache_size) {
225	3.07k	if (mxg->cache_size > 0) {
226	2.20k	memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
227	2.20k	}
228	3.07k	mxg->buffer_ptr = mxg->buffer;
229	3.07k	}
230
231	13.9k	return pkt->size;
232	58.1k	} else if (marker == COM && size >= 18 &&
233	58.1k	!strncmp(startmarker_ptr + 4, "MXF", 3)) {
234		/* time (GMT) of video frame in usec since 1970, little-endian */
235	52.6k	mxg->dts = AV_RL64(startmarker_ptr + 12);
236	52.6k	}
237	72.1k	}
238	2.90M	} else {
239		/* start marker not found */
240	20.2k	mxg->buffer_ptr = search_end;
241	20.2k	mxg->cache_size = OVERREAD_SIZE;
242	20.2k	}
243	2.92M	}
244
245	7.77k	return AVERROR_EOF;
246	1.12M	}
247
248		static int mxg_close(struct AVFormatContext *s)
249	7.01k	{
250	7.01k	MXGContext *mxg = s->priv_data;
251	7.01k	av_freep(&mxg->buffer);
252	7.01k	return 0;
253	7.01k	}
254
255		const FFInputFormat ff_mxg_demuxer = {
256		.p.name = "mxg",
257		.p.long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"),
258		.p.extensions = "mxg",
259		.priv_data_size = sizeof(MXGContext),
260		.read_header = mxg_read_header,
261		.read_packet = mxg_read_packet,
262		.read_close = mxg_close,
263		};