使用 FFMpeg for android 解码视频
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【中文标题】使用 FFMpeg for android 解码视频【英文标题】：Decoding Video using FFMpeg for android 【发布时间】：2012-07-04 14:17:43 【问题描述】：我尝试使用互联网上提供的示例示例中的 FFMpeg 库解码视频，我使用新版本的 ffmpeg 解决了这个问题， 这是我从类文件中调用的代码，
private static native int decodeVideo(String filename);
decodeVideo(getString(R.string._sdcard_abc_3gp));
现在在位于 JNI 目录的 .c 文件中，我编写了这段代码，
jint Java_ru_dzakhov_ffmpeg_test_MainActivity_decodeVideo(JNIEnv* env, jobject
javaThis,jstring filename)
AVFormatContext *pFormatCtx;
int i, videoStream;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameRGB;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
// Register all formats and codecs
av_register_all();
// Open video file
const jbyte *str;
str = (*env)->GetStringUTFChars(env, filename, NULL);
if(av_open_input_file(&pFormatCtx, str, NULL, 0, NULL)!=0)
LOGI("Can't open file '%s'\n", str);
return 1;
else
LOGI("File is opened\n");
LOGI("File '%s', Codec %s",pFormatCtx->filename,pFormatCtx->iformat->name);
// Dump information about file onto standard error
LOGI("dump_format");
dump_format(pFormatCtx, 0, filename, 0);
LOGI("dump_format DONE");
// Find the first video stream
videoStream=-1;
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO)
//if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
LOGI("videoStream:: %d",videoStream);
videoStream=i;
break;
if(videoStream==-1)
return -1; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtx=pFormatCtx->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL)
fprintf(stderr, "Unsupported codec!\n");
LOGI("Unsupported codec!\n");
return -1; // Codec not found
// Open codec
if(avcodec_open(pCodecCtx, pCodec)<0)
LOGI("Codec Opened!\n");
return -1; // Could not open codec
// Allocate video frame
pFrame=avcodec_alloc_frame();
// Allocate an AVFrame structure
pFrameRGB=avcodec_alloc_frame();
if(pFrameRGB==NULL)
LOGI("checking --->>> pFrameRGB==NULL\n");
return -1;
// Determine required buffer size and allocate buffer
LOGI("Determine required buffer size and allocate buffer\n");
numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
pCodecCtx->height);
LOGI("numBytes %d",numBytes);
buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
// Assign appropriate parts of buffer to image planes in pFrameRGB
// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
// of AVPicture
avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
pCodecCtx->width, pCodecCtx->height);
// Read frames and save first five frames to disk
i=0;
while(av_read_frame(pFormatCtx, &packet)>=0)
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
// Decode video frame
avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,&packet);
//packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
// Convert the image from its native format to RGB
/*Temporarily down
*
* img_convert((AVPicture *)pFrameRGB, PIX_FMT_RGB24,
(AVPicture*)pFrame, pCodecCtx->pix_fmt, pCodecCtx->width,pCodecCtx->height);*/
// Save the frame to phone memory
LOGI("Saving Frame\n");
SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, ++i);
LOGI("After Saving Frame\n");
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
// Free the RGB image
av_free(buffer);
av_free(pFrameRGB);
// Free the YUV frame
av_free(pFrame);
// Close the codec
avcodec_close(pCodecCtx);
// Close the video file
av_close_input_file(pFormatCtx);
return 0;
编译代码后，我在日志中得到了这个，
07-04 10:58:38.961: D/dalvikvm(1010): Trying to load lib /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so 0x4051e878
07-04 10:58:38.971: D/dalvikvm(1010): Added shared lib /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so 0x4051e878
07-04 10:58:38.971: D/dalvikvm(1010): No JNI_OnLoad found in /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so 0x4051e878, skipping init
07-04 10:58:39.011: I/System.out(1010): Creating Engine
07-04 10:58:39.011: I/mylib(1010): initiated
07-04 10:58:39.011: I/System.out(1010): Decoding Video
07-04 10:58:39.011: I/System.out(1010): passing video::/sdcard/NativeMedia.ts
07-04 10:58:39.101: W/dalvikvm(231): disableGcForExternalAlloc: false
07-04 10:58:39.121: I/DEBUG(71): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
07-04 10:58:39.121: I/DEBUG(71): Build fingerprint: 'htc_asia_india/htc_icong/icong:2.3.3/GRI40/68450.5:user/release-keys'
07-04 10:58:39.121: I/DEBUG(71): pid: 1010, tid: 1010 >>> ru.dzakhov.ffmpeg.test <<<
07-04 10:58:39.121: I/DEBUG(71): signal 4 (SIGILL), code 1 (ILL_ILLOPC), fault addr 8102de90
07-04 10:58:39.121: I/DEBUG(71): r0 0000ac28 r1 40521b98 r2 40526340 r3 42157cc8
07-04 10:58:39.121: I/DEBUG(71): r4 bee7d368 r5 00000004 r6 40521b98 r7 42157c88
07-04 10:58:39.121: I/DEBUG(71): r8 bee7d348 r9 42157c80 10 42157c6c fp 42f0f04c
07-04 10:58:39.121: I/DEBUG(71): ip 8102de91 sp bee7d348 lr 80018378 pc 8102de90 cpsr a0000030
07-04 10:58:39.121: I/DEBUG(71): d0 4140000041600000 d1 3ff0000041680000
07-04 10:58:39.121: I/DEBUG(71): d2 bf80000000000000 d3 0000000000000000
07-04 10:58:39.121: I/DEBUG(71): d4 0000000000000000 d5 3ff000003f800000
07-04 10:58:39.121: I/DEBUG(71): d6 bff000003f800000 d7 4160000000000000
07-04 10:58:39.121: I/DEBUG(71): d8 0000000000000000 d9 0000000000000000
07-04 10:58:39.121: I/DEBUG(71): d10 0000000000000000 d11 0000000000000000
07-04 10:58:39.121: I/DEBUG(71): d12 0000000000000000 d13 0000000000000000
07-04 10:58:39.121: I/DEBUG(71): d14 0000000000000000 d15 0000000000000000
07-04 10:58:39.121: I/DEBUG(71): scr 20000012
07-04 10:58:39.221: I/DEBUG(71): #00 pc 0002de90 /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so
07-04 10:58:39.221: I/DEBUG(71): #01 pc 0004f13c /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #02 pc 0001d584 /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #03 pc 00022b8c /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #04 pc 00021a80 /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #05 pc 0006060a /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #06 pc 0006828e /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #07 pc 0001d584 /system/lib/libdvm.so
07-04 10:58:39.221: I/DEBUG(71): #08 pc 00022b8c /system/lib/libdvm.so
07-04 10:58:39.231: I/DEBUG(71): #09 pc 00021a80 /system/lib/libdvm.so
07-04 10:58:39.231: I/DEBUG(71): #10 pc 0006045c /system/lib/libdvm.so
07-04 10:58:39.231: I/DEBUG(71): #11 pc 0004c430 /system/lib/libdvm.so
07-04 10:58:39.231: I/DEBUG(71): #12 pc 00037638 /system/lib/libandroid_runtime.so
07-04 10:58:39.231: I/DEBUG(71): #13 pc 00038456 /system/lib/libandroid_runtime.so
07-04 10:58:39.231: I/DEBUG(71): #14 pc 00008ca2 /system/bin/app_process
07-04 10:58:39.231: I/DEBUG(71): #15 pc 00014f24 /system/lib/libc.so
07-04 10:58:39.231: I/DEBUG(71): code around pc:
07-04 10:58:39.231: I/DEBUG(71): 8102de70 003d9cd0 00000408 0029e598 0029e5de
07-04 10:58:39.231: I/DEBUG(71): 8102de80 0029e5d8 0029e5d8 0029e5cc 0029e5c8
07-04 10:58:39.231: I/DEBUG(71): 8102de90 4ff0e92d b0994604 f0004615 6823f945
07-04 10:58:39.231: I/DEBUG(71): 8102dea0 46294620 32a4f8d3 47982200 46044f81
07-04 10:58:39.231: I/DEBUG(71): 8102deb0 a8172300 22004621 9300447f f9c0f060
07-04 10:58:39.231: I/DEBUG(71): code around lr:
07-04 10:58:39.231: I/DEBUG(71): 80018358 3497c004 3488c004 3afffff9 e2888004
07-04 10:58:39.231: I/DEBUG(71): 80018368 eafffff9 e899000c e594c008 e12fff3c
07-04 10:58:39.231: I/DEBUG(71): 80018378 e3550000 1594c00c 188c0003 e914a3f0
07-04 10:58:39.231: I/DEBUG(71): 80018388 e1a05e22 e5946004 e3a02000 e4d6c001
07-04 10:58:39.231: I/DEBUG(71): 80018398 e35c0000 0a000007 e2822001 e35c0044
07-04 10:58:39.231: I/DEBUG(71): stack:
07-04 10:58:39.231: I/DEBUG(71): bee7d308 000001b4
07-04 10:58:39.231: I/DEBUG(71): bee7d30c c0000000
07-04 10:58:39.231: I/DEBUG(71): bee7d310 80018540 /system/lib/libdvm.so
07-04 10:58:39.231: I/DEBUG(71): bee7d314 0000cf98
07-04 10:58:39.231: I/DEBUG(71): bee7d318 42157c6c
07-04 10:58:39.231: I/DEBUG(71): bee7d31c afd139d9 /system/lib/libc.so
07-04 10:58:39.231: I/DEBUG(71): bee7d320 0002de91
07-04 10:58:39.241: I/DEBUG(71): bee7d324 0000000e
07-04 10:58:39.241: I/DEBUG(71): bee7d328 80018540 /system/lib/libdvm.so
07-04 10:58:39.241: I/DEBUG(71): bee7d32c 00000070
07-04 10:58:39.241: I/DEBUG(71): bee7d330 42157c6c
07-04 10:58:39.241: I/DEBUG(71): bee7d334 00238100
07-04 10:58:39.241: I/DEBUG(71): bee7d338 00000000
07-04 10:58:39.241: I/DEBUG(71): bee7d33c 00000000
07-04 10:58:39.241: I/DEBUG(71): bee7d340 df002777
07-04 10:58:39.241: I/DEBUG(71): bee7d344 e3a070ad
07-04 10:58:39.241: I/DEBUG(71): #00 bee7d348 423692b4
07-04 10:58:39.241: I/DEBUG(71): bee7d34c 0000cf98
07-04 10:58:39.241: I/DEBUG(71): bee7d350 40521b98
07-04 10:58:39.241: I/DEBUG(71): bee7d354 8102de91 /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so
07-04 10:58:39.241: I/DEBUG(71): bee7d358 80018540 /system/lib/libdvm.so
07-04 10:58:39.241: I/DEBUG(71): bee7d35c 0000cf98
07-04 10:58:39.241: I/DEBUG(71): bee7d360 bee7d368
07-04 10:58:39.241: I/DEBUG(71): bee7d364 800499df /system/lib/libdvm.so
07-04 10:58:39.241: I/DEBUG(71): bee7d368 42157c80
07-04 10:58:39.241: I/DEBUG(71): bee7d36c 42d58795
07-04 10:58:39.241: I/DEBUG(71): bee7d370 8102de91 /data/data/ru.dzakhov.ffmpeg.test/lib/libmylib.so
07-04 10:58:39.241: I/DEBUG(71): bee7d374 bee7d418
07-04 10:58:39.241: I/DEBUG(71): bee7d378 00016de0
07-04 10:58:39.241: I/DEBUG(71): bee7d37c 0000ac28
07-04 10:58:39.241: I/DEBUG(71): bee7d380 00000001
07-04 10:58:39.241: I/DEBUG(71): bee7d384 bee7d418
07-04 10:58:39.241: I/DEBUG(71): bee7d388 42157c80
07-04 10:58:39.241: I/DEBUG(71): bee7d38c 40521b98
07-04 10:58:39.241: I/DEBUG(71): bee7d390 423692b4
07-04 10:58:39.241: I/DEBUG(71): bee7d394 800499a1 /system/lib/libdvm.so
07-04 10:58:39.241: I/DEBUG(71): bee7d398 42157c80
07-04 10:58:39.241: I/DEBUG(71): bee7d39c 8004f13f /system/lib/libdvm.so
07-04 10:58:39.241: I/DEBUG(71): #01 bee7d3a0 00000002
07-04 10:58:39.251: I/DEBUG(71): bee7d3a4 0000000e
07-04 10:58:39.251: I/DEBUG(71): bee7d3a8 bee7d418
07-04 10:58:39.251: I/DEBUG(71): bee7d3ac 0000cf98
07-04 10:58:39.251: I/DEBUG(71): bee7d3b0 400198b8
07-04 10:58:39.251: I/DEBUG(71): bee7d3b4 42d5861c
07-04 10:58:39.251: I/DEBUG(71): bee7d3b8 42157c98
07-04 10:58:39.251: I/DEBUG(71): bee7d3bc bee7d410
07-04 10:58:39.251: I/DEBUG(71): bee7d3c0 40521b98
07-04 10:58:39.251: I/DEBUG(71): bee7d3c4 8001d588 /system/lib/libdvm.so
无法理解到底是什么问题？ 这里使用了 SaveFrame 函数，看起来像，
void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame)
FILE *pFile;
char szFilename[32];
int y;
// Open file
LOGI("Opening file!");
sprintf(szFilename, "frame%d.ppm", iFrame);
pFile=fopen(szFilename, "wb");
if(pFile==NULL)
return;
// Write header
fprintf(pFile, "P6\n%d %d\n255\n", width, height);
//LOGI("width::"+width+"Height::"+height);
// Write pixel data
for(y=0; y<height; y++)
LOGI("writing file");
fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);
// Close file
fclose(pFile);
在日志中我没有得到我放在代码中的任何日志！
请帮帮我，
谢谢
【问题讨论】：
groups.google.com/forum/?fromgroups#!topic/android-ndk/… 您的二进制文件可能使用了您的设备不支持的某些指令。请您在android NDK中使用objdump -d，并找出您libmylib.so的地址2de90处的指令是什么？
您应该尝试缩小崩溃位置。尝试在 C 函数的入口处发出第一条日志消息，以查看日志记录是否有效。目前，av_register_all 和 av_open_input_file 等大型 ffmpeg 函数必须在您看到第一条日志消息之前传递。
嗨@drnous，我之前试过但没有结果。 :(
或者你可以使用一些已知可以工作的预编译包，比如JavaCV...
【参考方案1】：
查看导致问题的指令...
$ rasm2 -a arm -d 4ff0e92d stclcs 0, cr15, [r9, #316]！
stc 指令documentation.
搜索它，从用户空间可能无法做到这一点：Getting ILL_ILLOPC (illegal opcode) when trying to execute MRC or MCR instructions on Android
那么，这应该不是你的问题，对吧？ :)
尝试仅在本机中打印一些日志消息（或至少在 av_register_all() 之前这样做），不要添加任何其他额外的库，看看你是否做对了。
【讨论】：
【参考方案2】：我认为您使用不适合 Android 的编译器选项构建 FFmpeg。
我建议关注android-ffmpeg-tutorial，它有适用于 Android 上的 FFmpeg 的工作示例。它也参考了有关为 Android 构建 FFmpeg 的文章。
您可能还想看看更高级的 Android 代码和 FFmpeg 播放器AndroidFFmpeg，即使在 Genymotion 模拟器中也可以正常工作，我测试过。详细说明如何构建，开箱即用。
您的代码使用了已弃用的 FFmpeg 调用，上面链接中的代码已为此更新。
【讨论】：
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