ffmpeg 新老接口问题及对照集锦

转自：http://blog.csdn.net/cosmoslife/article/details/7618616

网上很多关于ffmpeg (libav)的资料都是N年以前的，而事实上ffmpeg数年来一直在“以时俱进”，因此无论是一些新手，或者号称为老手的人，有时候难免出头痛。。。。。。

为了解决大家的头痛的问题，特列一个贴子，把ffmpeg相关的一些常见的、版本的问题列举出来，供大家参考，同时也请大家一起补充。

1) 不认识guess_format.

解决： #define guess_format av_guess_format

接口不变。

2) 不认识av_alloc_format_context

解决： #define av_alloc_format_context avformat_alloc_output_context

接口调整。

3) 不认识CODEC_TYPE_VIDEO 和 CODEC_TYPE_AUDIO

解决：

#define CODEC_TYPE_VIDEO AVMEDIA_TYPE_VIDEO

#define CODEC_TYPE_AUDIO AVMEDIA_TYPE_AUDIO

4) 不认识audio_resample_init

解决：#define audio_resample_init av_audio_resample_init

接口调整。

5) avcodec_decode_video 到 avcodec_decode_video2接口调整

旧代码：

len = avcodec_decode_video(c, (short *)outbuf, &out_size, inbuf_ptr, size);

新代码：

av_init_packet(&pkt);

pkt.data = (unsigned char*)inbuf_ptr;

pkt.size = size;

len = avcodec_decode_video2(c, &tmpFrame, &got_picture, &pkt);

6)url_fopen变成新的接口 avio_open
新版代码：
/**

* Create and initialize a AVIOContext for accessing the

* resource indicated by url.

* @note When the resource indicated by url has been opened in

* read+write mode, the AVIOContext can be used only for writing.

*

* @param s Used to return the pointer to the created AVIOContext.

* In case of failure the pointed to value is set to NULL.

* @param flags flags which control how the resource indicated by url

* is to be opened

* @return 0 in case of success, a negative value corresponding to an

* AVERROR code in case of failure

*/

int avio_open(AVIOContext **s, const char *url, int flags);

7)av_write_header变成了avformat_write_header
新版代码:
/**

* @addtogroup lavf_encoding

* @{

*/

/**

* Allocate the stream private data and write the stream header to

* an output media file.

*

* @param s Media file handle, must be allocated with avformat_alloc_context().

* Its oformat field must be set to the desired output format;

* Its pb field must be set to an already openened AVIOContext.

* @param options An AVDictionary filled with AVFormatContext and muxer-private options.

* On return this parameter will be destroyed and replaced with a dict containing

* options that were not found. May be NULL.

*

* @return 0 on success, negative AVERROR on failure.

*

* @see av_opt_find, av_dict_set, avio_open, av_oformat_next.

*/

int avformat_write_header(AVFormatContext *s, AVDictionary **options);

8)旧版宏定义：PKT_FLAG_KEY 新版宏定义：AV_PKT_FLAG_KEY

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As Gabi points out, that URL has most of the replacements of the deprecated constants.

However, it lacks a few of them, so I'll post all the changes that your output indicates are necessary to get through this compilation step:

avcodec_init -> avcodec_register_all
av_open_input_file -> avformat_open_input

It's probably worth noting here that av_set_parameters was deprecated and completely scrapped, so you should specify parameters in the call to avformat_open_input now.

AVFormatContext.file_size -> avio_size()
URL_WRONLY -> AVIO_FLAG_WRITE
url_fopen -> avio_open
url_fclose -> avio_close
SAMPLE_FMT_U8 -> AV_SAMPLE_FMT_U8
SAMPLE_FMT_S16 -> AV_SAMPLE_FMT_S16
SAMPLE_FMT_S32 -> AV_SAMPLE_FMT_S32
SAMPLE_FMT_FLT -> AV_SAMPLE_FMT_FLT
FF_I_TYPE -> AV_PICTURE_TYPE_I

That should cover all of your actual errors. If there's just a warning, then take some time to figure out what they're phasing in!

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网上很多关于ffmpeg (libav)的资料都是N年以前的，而事实上ffmpeg数年来一直在“以时俱进”，因此无论是一些新手，或者号称为老手的人，有时候难免出头痛。。。。。。

为了解决大家的头痛的问题，特列一个贴子，把ffmpeg相关的一些常见的、版本的问题列举出来，供大家参考，同时也请大家一起补充。

1) 不认识guess_format.

解决： #define guess_format av_guess_format

接口不变。

2) 不认识av_alloc_format_context

解决： #define av_alloc_format_context avformat_alloc_output_context

接口调整。

3) 不认识CODEC_TYPE_VIDEO 和 CODEC_TYPE_AUDIO

解决：

#define CODEC_TYPE_VIDEO AVMEDIA_TYPE_VIDEO

#define CODEC_TYPE_AUDIO AVMEDIA_TYPE_AUDIO

4) 不认识audio_resample_init

解决：#define audio_resample_init av_audio_resample_init

接口调整。

5) avcodec_decode_video 到 avcodec_decode_video2接口调整

旧代码：

len = avcodec_decode_video(c, (short *)outbuf, &out_size, inbuf_ptr, size);

复制代码
新代码：

av_init_packet(&pkt);

pkt.data = (unsigned char*)inbuf_ptr;

pkt.size = size;

len = avcodec_decode_video2(c, &tmpFrame, &got_picture, &pkt);

复制代码

av_open_input_file

/opt/workspace/android/EasyPlayer/jni/EasyPlayer/EasyPlayer.cpp:483: warning: 'int av_open_input_file(AVFormatContext**, const char*, AVInputFormat*,
int, AVFormatParameters*)' is deprecated (declared at /opt/workspace/android/EasyPlayer/jni/EasyPlayer/../include/libavformat/avformat.h:1480)

新接口：

#ifdef _FFMPEG_0_6__

if(av_open_input_file(&ffmpeg_fields.pFormatCtx, _filePath, NULL, 0, NULL) != 0)

#else

if (avformat_open_input(&ffmpeg_fields.pFormatCtx, _filePath, NULL, NULL) != 0)

#endif

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av_find_stream_info

/opt/workspace/android/EasyPlayer/jni/EasyPlayer/EasyPlayer.cpp:494: warning: 'int av_find_stream_info(AVFormatContext*)' is deprecated (declared
at /opt/workspace/android/EasyPlayer/jni/EasyPlayer/../include/libavformat/avformat.h:1526)

新接口：

#ifdef _FFMPEG_0_6__

if(av_find_stream_info(ffmpeg_fields.pFormatCtx) < 0)

#else

if (avformat_find_stream_info(ffmpeg_fields.pFormatCtx, NULL) < 0)

#endif

复制代码
av_close_input_file

/opt/workspace/android/EasyPlayer/jni/EasyPlayer/EasyPlayer.cpp:522: warning: 'void av_close_input_file(AVFormatContext*)' is deprecated (declared
at /opt/workspace/android/EasyPlayer/jni/EasyPlayer/../include/libavformat/avformat.h:1706)

新接口：

#ifdef _FFMPEG_0_6__

av_close_input_file(ffmpeg_fields.pFormatCtx);

#else

avformat_close_input(&ffmpeg_fields.pFormatCtx);

#endif

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注意，这个是个２级指针。

avcodec_open2

新出来的avcodec_open2接口支持一些编解码特性的指定。

#ifdef __FFMPEG_0_6__

if (avcodec_open(ffmpeg_video.codec_ctx, ffmpeg_video.codec) < 0)

#else

if (avcodec_open2(ffmpeg_video.codec_ctx, ffmpeg_video.codec, NULL) < 0)

#endif

avcodec_init

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:20: warning: 'void avcodec_init()' is deprecated (declared at /opt/workspace/android/EasyIPCam/jni/libeasycodec/../3rdparty/libavcodec/avcodec.h:3932)

这个function已经不再需要了，当你调用avcodec_register()或者 avcodec_register_all()时，ffmpeg会自动调用它。所以放心大胆的移除掉就可以了。

url_fclose url_fopen url_fseek等等

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:67: warning: 'int url_fclose(AVIOContext*)' is deprecated (declared at /opt/workspace/android/EasyIPCam/jni/libeasycodec/../3rdparty/libavformat/avio.h:324)

这一系统的接口都只需要在前面加一个avio_的前缀就可以了，如：avio_close()。

avcodec_alloc_context()

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:111: warning: 'AVCodecContext* avcodec_alloc_context()' is deprecated (declared
at /opt/workspace/android/EasyIPCam/jni/libeasycodec/../3rdparty/libavcodec/avcodec.h:4025)

使用最新接口：avcodec_alloc_context3()

m_pACodec = avcodec_find_encoder((CodecID)nCodecID);

if(!m_pACodec) return false;

m_pAContext = avcodec_alloc_context3(m_pACodec);

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av_get_bits_per_sample_format

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:143: warning: 'int av_get_bits_per_sample_format(AVSampleFormat)' is deprecated
(declared at /opt/workspace/android/EasyIPCam/jni/libeasycodec/../3rdparty/libavcodec/avcodec.h:4529)

新接口改为av_get_bytes_per_sample（反正音频bits per sample是8的倍数，不是8就是16，直接用byte比用bit更好）

audio_resample_init

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:157: error: 'audio_resample_init' was not declared in this scope

新接口：av_audio_resample_init，原先我以为ffmpeg要支持超过2
channels的resample，后来一看resample.c里的实现，结果发现还是只能支持mono和stereo

多出来的几个参数，给填default值:

AV_SAMPLE_FMT_S16,

AV_SAMPLE_FMT_S16,

TAPS, 10, 0, 0.8

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详见resample.c，或者参考RTSPPlayer中的easyffmpeg.cpp.

PKT_FLAG_KEY

没什么好说的，直接在前面加个AV_的前缀：AV_PKT_FLAG_KEY

av_alloc_format_context

/opt/workspace/android/EasyIPCam/jni/libeasycodec/EasyCodec.cpp:722: error: 'av_alloc_format_context' was not declared in this scope

这个前面两位同仁有提到不同，但不说怎么个不同法，实在可恨，我直接写个例子：

avformat_alloc_output_context2(&m_pFormatCtx, pOutputFmt, "avi", pFileName);

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