libavformat/mxg.c - nest-android-app/ffmpeg - Git at Google

 /*
  * 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 "libavcodec/mjpeg.h"
 #include "avformat.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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
     video_st->codec->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->codec->codec_type = AVMEDIA_TYPE_AUDIO;
     audio_st->codec->codec_id = AV_CODEC_ID_PCM_ALAW;
     audio_st->codec->channels = 1;
     audio_st->codec->channel_layout = AV_CH_LAYOUT_MONO;
     audio_st->codec->sample_rate = 8000;
     audio_st->codec->bits_per_coded_sample = 8;
     audio_st->codec->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;

     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;
                 }

                 pkt->pts = pkt->dts = mxg->dts;
                 pkt->stream_index = 0;
                 pkt->buf  = 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) {
                         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 */
                     /* time (GMT) of first sample in usec since 1970, little-endian */
                     pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
                     pkt->stream_index = 1;
                     pkt->buf  = 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 ff_mxg_demuxer = {
     .name           = "mxg",
     .long_name      = NULL_IF_CONFIG_SMALL("MxPEG clip"),
     .priv_data_size = sizeof(MXGContext),
     .read_header    = mxg_read_header,
     .read_packet    = mxg_read_packet,
     .read_close     = mxg_close,
     .extensions     = "mxg",
 };
	/*
	* 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 "libavcodec/mjpeg.h"
	#include "avformat.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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
	video_st->codec->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->codec->codec_type = AVMEDIA_TYPE_AUDIO;
	audio_st->codec->codec_id = AV_CODEC_ID_PCM_ALAW;
	audio_st->codec->channels = 1;
	audio_st->codec->channel_layout = AV_CH_LAYOUT_MONO;
	audio_st->codec->sample_rate = 8000;
	audio_st->codec->bits_per_coded_sample = 8;
	audio_st->codec->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;

	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;
	}

	pkt->pts = pkt->dts = mxg->dts;
	pkt->stream_index = 0;
	pkt->buf = 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) {
	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 */
	/* time (GMT) of first sample in usec since 1970, little-endian */
	pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
	pkt->stream_index = 1;
	pkt->buf = 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 ff_mxg_demuxer = {
	.name = "mxg",
	.long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"),
	.priv_data_size = sizeof(MXGContext),
	.read_header = mxg_read_header,
	.read_packet = mxg_read_packet,
	.read_close = mxg_close,
	.extensions = "mxg",
	};