Mobotix .mxg demuxer

Patch by Anatoly Nenashev, anatoly d nenashev a ovsoft d ru

Originally committed as revision 25831 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 251 insertions, 0 deletions

diff --git a/libavformat/mxg.c b/libavformat/mxg.c
new file mode 100644
index 0000000000..e7791e871b
--- /dev/null
+++ b/libavformat/mxg.c
@@ -0,0 +1,251 @@
+/*
+ * 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/intreadwrite.h"
+#include "libavcodec/mjpeg.h"
+#include "avformat.h"
+#include "avio.h"
+
+#define VIDEO_STREAM_INDEX 0
+#define AUDIO_STREAM_INDEX 1
+#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, AVFormatParameters *ap)
+{
+    AVStream *video_st, *audio_st;
+    MXGContext *mxg = s->priv_data;
+
+    /* video parameters will be extracted from the compressed bitstream */
+    video_st = av_new_stream(s, VIDEO_STREAM_INDEX);
+    if (!video_st)
+        return AVERROR(ENOMEM);
+    video_st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
+    video_st->codec->codec_id = CODEC_ID_MXPEG;
+    av_set_pts_info(video_st, 64, 1, 1000000);
+
+    audio_st = av_new_stream(s, AUDIO_STREAM_INDEX);
+    if (!audio_st)
+        return AVERROR(ENOMEM);
+    audio_st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    audio_st->codec->codec_id = CODEC_ID_PCM_ALAW;
+    audio_st->codec->channels = 1;
+    audio_st->codec->sample_rate = 8000;
+    audio_st->codec->bits_per_coded_sample = 8;
+    audio_st->codec->block_align = 1;
+    av_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 = *(uint32_t*)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;
+    int ret;
+
+    /* reallocate internal buffer */
+    if (current_pos > current_pos + cache_size)
+        return AVERROR(ENOMEM);
+    if (mxg->soi_ptr) soi_pos = mxg->soi_ptr - mxg->buffer;
+    mxg->buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
+                                  current_pos + cache_size +
+                                  FF_INPUT_BUFFER_PADDING_SIZE);
+    if (!mxg->buffer)
+        return AVERROR(ENOMEM);
+    mxg->buffer_ptr = mxg->buffer + current_pos;
+    if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos;
+
+    /* get data */
+    ret = get_buffer(s->pb, mxg->buffer_ptr + mxg->cache_size,
+                     cache_size - mxg->cache_size);
+    if (ret < 0)
+        return ret;
+
+    mxg->cache_size += ret;
+
+    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 (!url_feof(s->pb) && !url_ferror(s->pb)){
+        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;
+                }
+
+                pkt->pts = pkt->dts = mxg->dts;
+                pkt->stream_index = VIDEO_STREAM_INDEX;
+                pkt->destruct = NULL;
+                pkt->size = mxg->buffer_ptr - mxg->soi_ptr;
+                pkt->data = mxg->soi_ptr;
+
+                if (mxg->soi_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;
+                }
+                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 */
+                    /* time (GMT) of first sample in usec since 1970, little-endian */
+                    pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
+                    pkt->stream_index = AUDIO_STREAM_INDEX;
+                    pkt->destruct = NULL;
+                    pkt->size = size - 14;
+                    pkt->data = startmarker_ptr + 16;
+
+                    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;
+}
+
+AVInputFormat mxg_demuxer = {
+    .name = "mxg",
+    .long_name = NULL_IF_CONFIG_SMALL("MxPEG clip file format"),
+    .priv_data_size = sizeof(MXGContext),
+    .read_header = mxg_read_header,
+    .read_packet = mxg_read_packet,
+    .read_close = mxg_close,
+    .extensions = "mxg"
+};