ffmpeg 新老接口问题及对照集锦

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 ***MEDIA_TYPE_VIDEO

#define CODEC_TYPE_AUDIO ***MEDIA_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 ***IOContext for accessing the

* resource indicated by url.

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

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

*

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

* 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

* ***ERROR code in case of failure

*/

int avio_open(***IOContext **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 ***IOContext.

* @param options An ***Dictionary filled with ***FormatContext 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 ***ERROR on failure.

*

* @see av_opt_find, av_dict_set, avio_open, av_oformat_next.

*/

int avformat_write_header(***FormatContext *s, ***Dictionary **options);

8)旧版宏定义：PKT_FLAG_KEY 新版宏定义：***_PKT_FLAG_KEY

持续更新中.....................
不全的地方，知道的给补上