基于最简单的FFmpeg采样读取内存读写：存储转

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpeGlhb2h1YTEwMjA=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />

代码

以下直接贴上代码：

/**

 * 最简单的基于FFmpeg的内存读写样例（内存转码器）

 * Simplest FFmpeg mem Transcoder

 *

 * 雷霄骅，张晖

 * leixiaohua1020@126.com

 * 中国传媒大学/数字电视技术

 * Communication University of China / Digital TV Technology

 * http://blog.csdn.net/leixiaohua1020

 *

 * 本程序实现了随意格式视频数据（比如MPEG2）转码为H.264码流数据。

 * 本程序并非对文件进行处理，而是对内存中的视频数据进行处理。

 * 它从内存读取数据，而且将转码后的数据输出到内存中。

 * 是最简单的使用FFmpeg读写内存的样例。

 *

 * This software convert video bitstream (Such as MPEG2) to H.264

 * bitstream. It read video bitstream from memory (not from a file),

 * convert it to H.264 bitstream, and finally output to another memory.

 * It's the simplest example to use FFmpeg to read (or write) from

 * memory.

 *

 */

#include <stdio.h>

extern "C"

{

#include "libavcodec/avcodec.h"

#include "libavformat/avformat.h"

#include "libavutil/avutil.h"

#include "libavutil/opt.h"

#include "libavutil/pixdesc.h"

};

FILE *fp_open;

FILE *fp_write;

//Read File

int read_buffer(void *opaque, uint8_t *buf, int buf_size){

	if(!feof(fp_open)){

		int true_size=fread(buf,1,buf_size,fp_open);

		return true_size;

	}else{

		return -1;

	}

}

//Write File

int write_buffer(void *opaque, uint8_t *buf, int buf_size){

	if(!feof(fp_write)){

		int true_size=fwrite(buf,1,buf_size,fp_write);

		return true_size;

	}else{

		return -1;

	}

}

int flush_encoder(AVFormatContext *fmt_ctx,unsigned int stream_index)

{

    int ret;

    int got_frame;

	AVPacket enc_pkt;

    if (!(fmt_ctx->streams[stream_index]->codec->codec->capabilities &

                CODEC_CAP_DELAY))

        return 0;

    while (1) {

        av_log(NULL, AV_LOG_INFO, "Flushing stream #%u encoder\n", stream_index);

        //ret = encode_write_frame(NULL, stream_index, &got_frame);

        enc_pkt.data = NULL;

		enc_pkt.size = 0;

		av_init_packet(&enc_pkt);

		ret = avcodec_encode_video2 (fmt_ctx->streams[stream_index]->codec, &enc_pkt,

				NULL, &got_frame);

		av_frame_free(NULL);

		if (ret < 0)

			break;

		if (!got_frame)

		{ret=0;break;}

		/* prepare packet for muxing */

		enc_pkt.stream_index = stream_index;

		enc_pkt.dts = av_rescale_q_rnd(enc_pkt.dts,

				fmt_ctx->streams[stream_index]->codec->time_base,

				fmt_ctx->streams[stream_index]->time_base,

				(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

		enc_pkt.pts = av_rescale_q_rnd(enc_pkt.pts,

				fmt_ctx->streams[stream_index]->codec->time_base,

				fmt_ctx->streams[stream_index]->time_base,

				(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

		enc_pkt.duration = av_rescale_q(enc_pkt.duration,

				fmt_ctx->streams[stream_index]->codec->time_base,

				fmt_ctx->streams[stream_index]->time_base);

		av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");

		/* mux encoded frame */

		ret = av_write_frame(fmt_ctx, &enc_pkt);

		if (ret < 0)

            break;

    }

    return ret;

}

int main(int argc, char* argv[])

{

	int ret;

	AVFormatContext* ifmt_ctx=NULL;

	AVFormatContext* ofmt_ctx=NULL;

	AVPacket packet,enc_pkt;

	AVFrame *frame = NULL;

	enum AVMediaType type;

	unsigned int stream_index;

	unsigned int i=0;

	int got_frame,enc_got_frame;

	AVStream *out_stream;

	AVStream *in_stream;

	AVCodecContext *dec_ctx, *enc_ctx;

	AVCodec *encoder;

	fp_open = fopen("cuc60anniversary_start.ts", "rb");	//视频源文件

	fp_write=fopen("cuc60anniversary_start.h264","wb+"); //输出文件

	av_register_all();

	ifmt_ctx=avformat_alloc_context();

	avformat_alloc_output_context2(&ofmt_ctx, NULL, "h264", NULL);

	unsigned char* inbuffer=NULL;

	unsigned char* outbuffer=NULL;

	inbuffer=(unsigned char*)av_malloc(32768);

	outbuffer=(unsigned char*)av_malloc(32768);

	/*open input file*/

	AVIOContext *avio_in =avio_alloc_context(inbuffer, 32768,0,NULL,read_buffer,NULL,NULL);

	if(avio_in==NULL)

		goto end;

	ifmt_ctx->pb=avio_in;

	ifmt_ctx->flags=AVFMT_FLAG_CUSTOM_IO;

	if ((ret = avformat_open_input(&ifmt_ctx, "whatever", NULL, NULL)) < 0) {

		av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");

		return ret;

	}

	if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {

		av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");

		return ret;

	}

	for (i = 0; i < ifmt_ctx->nb_streams; i++) {

		AVStream *stream;

		AVCodecContext *codec_ctx;

		stream = ifmt_ctx->streams[i];

		codec_ctx = stream->codec;

		/* Reencode video & audio and remux subtitles etc. */

		if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO){

			/* Open decoder */

			ret = avcodec_open2(codec_ctx,

				avcodec_find_decoder(codec_ctx->codec_id), NULL);

			if (ret < 0) {

				av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);

				return ret;

			}

		}

	}

	//av_dump_format(ifmt_ctx, 0, "whatever", 0);

	/*open output file*/

	AVIOContext *avio_out =avio_alloc_context(outbuffer, 32768,0,NULL,NULL,write_buffer,NULL);

	if(avio_out==NULL)

		goto end;

	//avio_out->write_packet=write_packet;

	ofmt_ctx->pb=avio_out;

	ofmt_ctx->flags=AVFMT_FLAG_CUSTOM_IO;

	for (i = 0; i < 1; i++) {

		out_stream = avformat_new_stream(ofmt_ctx, NULL);

		if (!out_stream) {

			av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");

			return AVERROR_UNKNOWN;

		}

		in_stream = ifmt_ctx->streams[i];

		dec_ctx = in_stream->codec;

		enc_ctx = out_stream->codec;

		if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)

		{

			encoder = avcodec_find_encoder(AV_CODEC_ID_H264);

			enc_ctx->height = dec_ctx->height;

			enc_ctx->width = dec_ctx->width;

			enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;

			enc_ctx->pix_fmt = encoder->pix_fmts[0];

			enc_ctx->time_base = dec_ctx->time_base;

			//enc_ctx->time_base.num = 1;

			//enc_ctx->time_base.den = 25;

			//H264的必备选项，没有就会错

			enc_ctx->me_range=16;

			enc_ctx->max_qdiff = 4;

			enc_ctx->qmin = 10;

			enc_ctx->qmax = 51;

			enc_ctx->qcompress = 0.6;

			enc_ctx->refs=3;

			enc_ctx->bit_rate = 500000;

			ret = avcodec_open2(enc_ctx, encoder, NULL);

			if (ret < 0) {

				av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);

				return ret;

			}

		}

		else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {

			av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);

			return AVERROR_INVALIDDATA;

		} else {

			/* if this stream must be remuxed */

			ret = avcodec_copy_context(ofmt_ctx->streams[i]->codec,

				ifmt_ctx->streams[i]->codec);

			if (ret < 0) {

				av_log(NULL, AV_LOG_ERROR, "Copying stream context failed\n");

				return ret;

			}

		}

		if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)

			enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;

	}

	//av_dump_format(ofmt_ctx, 0, "whatever", 1);

	/* init muxer, write output file header */

	ret = avformat_write_header(ofmt_ctx, NULL);

	if (ret < 0) {

		av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");

		return ret;

	}

	i=0;

	/* read all packets */

	while (1) {

		i++;

		if ((ret = av_read_frame(ifmt_ctx, &packet)) < 0)

			break;

		stream_index = packet.stream_index;

		if(stream_index!=0)

			continue;

		type = ifmt_ctx->streams[packet.stream_index]->codec->codec_type;

		av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n",

			stream_index);

		av_log(NULL, AV_LOG_DEBUG, "Going to reencode the frame\n");

		frame = av_frame_alloc();

		if (!frame) {

			ret = AVERROR(ENOMEM);

			break;

		}

		packet.dts = av_rescale_q_rnd(packet.dts,

			ifmt_ctx->streams[stream_index]->time_base,

			ifmt_ctx->streams[stream_index]->codec->time_base,

			(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

		packet.pts = av_rescale_q_rnd(packet.pts,

			ifmt_ctx->streams[stream_index]->time_base,

			ifmt_ctx->streams[stream_index]->codec->time_base,

			(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

		ret = avcodec_decode_video2(ifmt_ctx->streams[stream_index]->codec, frame,

			&got_frame, &packet);

		printf("Decode 1 Packet\tsize:%d\tpts:%d\n",packet.size,packet.pts);

		if (ret < 0) {

			av_frame_free(&frame);

			av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");

			break;

		}

		if (got_frame) {

			frame->pts = av_frame_get_best_effort_timestamp(frame);

			frame->pict_type=AV_PICTURE_TYPE_NONE;

			enc_pkt.data = NULL;

			enc_pkt.size = 0;

			av_init_packet(&enc_pkt);

			ret = avcodec_encode_video2 (ofmt_ctx->streams[stream_index]->codec, &enc_pkt,

				frame, &enc_got_frame);

			printf("Encode 1 Packet\tsize:%d\tpts:%d\n",enc_pkt.size,enc_pkt.pts);

			av_frame_free(&frame);

			if (ret < 0)

				goto end;

			if (!enc_got_frame)

				continue;

			/* prepare packet for muxing */

			enc_pkt.stream_index = stream_index;

			enc_pkt.dts = av_rescale_q_rnd(enc_pkt.dts,

				ofmt_ctx->streams[stream_index]->codec->time_base,

				ofmt_ctx->streams[stream_index]->time_base,

				(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

			enc_pkt.pts = av_rescale_q_rnd(enc_pkt.pts,

				ofmt_ctx->streams[stream_index]->codec->time_base,

				ofmt_ctx->streams[stream_index]->time_base,

				(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

			enc_pkt.duration = av_rescale_q(enc_pkt.duration,

				ofmt_ctx->streams[stream_index]->codec->time_base,

				ofmt_ctx->streams[stream_index]->time_base);

			av_log(NULL, AV_LOG_INFO, "Muxing frame %d\n",i);

			/* mux encoded frame */

			av_write_frame(ofmt_ctx,&enc_pkt);

			if (ret < 0)

				goto end;

		} else {

			av_frame_free(&frame);

		}

		av_free_packet(&packet);

	}

	/* flush encoders */

	for (i = 0; i < 1; i++) {

		/* flush encoder */

		ret = flush_encoder(ofmt_ctx,i);

		if (ret < 0) {

			av_log(NULL, AV_LOG_ERROR, "Flushing encoder failed\n");

			goto end;

		}

	}

	av_write_trailer(ofmt_ctx);

end:

	av_freep(avio_in);

	av_freep(avio_out);

	av_free(inbuffer);

	av_free(outbuffer);

	av_free_packet(&packet);

	av_frame_free(&frame);

	avformat_close_input(&ifmt_ctx);

	avformat_free_context(ofmt_ctx);

	fcloseall();

	if (ret < 0)

		av_log(NULL, AV_LOG_ERROR, "Error occurred\n");

	return (ret? 1:0);

}

结果

程序执行的结果例如以下图所看到的。

基于最简单的FFmpeg采样读取内存读写：存储转

转码前的视频信息使用MediaInfo查看例如以下图所看到的。

基于最简单的FFmpeg采样读取内存读写：存储转

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpeGlhb2h1YTEwMjA=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />

转码后的视频信息使用MediaInfo查看例如以下图所看到的。

基于最简单的FFmpeg采样读取内存读写：存储转

下载

simplest ffmpeg mem handler

项目主页

SourceForge：https://sourceforge.net/projects/simplestffmpegmemhandler/

Github：https://github.com/leixiaohua1020/simplest_ffmpeg_mem_handler

开源中国：http://git.oschina.net/leixiaohua1020/simplest_ffmpeg_mem_handler

CSDN下载地址：
http://download.csdn.net/detail/leixiaohua1020/8003731

本工程包括两个FFmpeg读写内存的样例：
simplest_ffmpeg_mem_player：基于FFmpeg的内存播放器。
simplest_ffmpeg_mem_transcoder：基于FFmpeg的内存转码器。

更新-1.1 (2015.2.13)=========================================

这次考虑到了跨平台的要求，调整了源码。经过这次调整之后，源码能够在以下平台编译通过：

VC++：打开sln文件就可以编译，无需配置。

cl.exe：打开compile_cl.bat就可以命令行下使用cl.exe进行编译。注意可能须要依照VC的安装路径调整脚本里面的參数。编译命令例如以下。

::VS2010 Environment

call "D:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat"

::include

@set INCLUDE=include;%INCLUDE%

::lib

@set LIB=lib;%LIB%

::compile and link

cl simplest_ffmpeg_mem_transcoder.cpp /link avcodec.lib avformat.lib avutil.lib ^

avdevice.lib avfilter.lib postproc.lib swresample.lib swscale.lib /OPT:NOREF

MinGW：MinGW命令行下执行compile_mingw.sh就可以使用MinGW的g++进行编译。编译命令例如以下。

g++ simplest_ffmpeg_mem_transcoder.cpp -g -o simplest_ffmpeg_mem_transcoder.exe \

-I /usr/local/include -L /usr/local/lib \

-lavcodec -lavformat -lavutil -lavdevice -lavfilter -lpostproc -lswresample -lswscale

GCC：Linux或者MacOS命令行下执行compile_gcc.sh就可以使用GCC进行编译。

编译命令例如以下。

gcc simplest_ffmpeg_mem_transcoder.cpp -g -o simplest_ffmpeg_mem_transcoder.out \

-I /usr/local/include -L /usr/local/lib \

-lavcodec -lavformat -lavutil -lavdevice -lavfilter -lpostproc -lswresample -lswscale

PS：相关的编译命令已经保存到了工程目录中

CSDN下载：http://download.csdn.net/detail/leixiaohua1020/8445795

SourceForge已经更新。

秒客网

基于最简单的FFmpeg采样读取内存读写：存储转

流程

代码

结果

下载

相关文章