libav

问题 I have two identical cameras connected and using Libav/FFmpeg. The option settings are: format = "dshow" input = "video=Videology USB-C Camera" However, I am not able to distinguish between the two identical cameras. If I try to print out the list of devices, I get the following: $> FFmpeg -list_devices true -f dshow -i dummy [dshow @ 02597f60] DirectShow video devices [dshow @ 02597f60] "Integrated Camera" [dshow @ 02597f60] "Videology USB-C Camera" Last message repeated 1 times [dshow @

问题 I have two identical cameras connected and using Libav/FFmpeg. The option settings are: format = "dshow" input = "video=Videology USB-C Camera" However, I am not able to distinguish between the two identical cameras. If I try to print out the list of devices, I get the following: $> FFmpeg -list_devices true -f dshow -i dummy [dshow @ 02597f60] DirectShow video devices [dshow @ 02597f60] "Integrated Camera" [dshow @ 02597f60] "Videology USB-C Camera" Last message repeated 1 times [dshow @

问题 Currently I am using libav* to encode H.264 videos. I want to add KLVPackets to the bitstream but do not know where to implement it. There is a struct within avcodec, but I am unsure of how to write it out to the frame metadata typedef struct { UID key; int64_t offset; uint64_t length; } KLVPacket; Current FFMPEG code (only left relevant code): av_register_all(); pOutputFormat = av_guess_format(NULL, fileName, NULL); pFormatCtx=avformat_alloc_context(); pVideoStream = av_new_stream(pFormatCtx

问题 Currently I am using libav* to encode H.264 videos. I want to add KLVPackets to the bitstream but do not know where to implement it. There is a struct within avcodec, but I am unsure of how to write it out to the frame metadata typedef struct { UID key; int64_t offset; uint64_t length; } KLVPacket; Current FFMPEG code (only left relevant code): av_register_all(); pOutputFormat = av_guess_format(NULL, fileName, NULL); pFormatCtx=avformat_alloc_context(); pVideoStream = av_new_stream(pFormatCtx

问题 Currently I am using libav* to encode H.264 videos. I want to add KLVPackets to the bitstream but do not know where to implement it. There is a struct within avcodec, but I am unsure of how to write it out to the frame metadata typedef struct { UID key; int64_t offset; uint64_t length; } KLVPacket; Current FFMPEG code (only left relevant code): av_register_all(); pOutputFormat = av_guess_format(NULL, fileName, NULL); pFormatCtx=avformat_alloc_context(); pVideoStream = av_new_stream(pFormatCtx

问题 Currently I am using libav* to encode H.264 videos. I want to add KLVPackets to the bitstream but do not know where to implement it. There is a struct within avcodec, but I am unsure of how to write it out to the frame metadata typedef struct { UID key; int64_t offset; uint64_t length; } KLVPacket; Current FFMPEG code (only left relevant code): av_register_all(); pOutputFormat = av_guess_format(NULL, fileName, NULL); pFormatCtx=avformat_alloc_context(); pVideoStream = av_new_stream(pFormatCtx

问题 Is LibAV/FFMpeg thread safe? For example. Could i read from a file using AVFormatContext* in one thread and decode the read packet it in another with simple additions of mutexes or is the thread safetyness of the library a "don't know don't care" type deal? I know that libav has basic support for encoder threads but i'm trying more of a blackbox type approach where i break it up into multiple threads (Source -> Decoder -> Filter -> Encoder -> Sink) and trying to understand the complications

问题 Is LibAV/FFMpeg thread safe? For example. Could i read from a file using AVFormatContext* in one thread and decode the read packet it in another with simple additions of mutexes or is the thread safetyness of the library a "don't know don't care" type deal? I know that libav has basic support for encoder threads but i'm trying more of a blackbox type approach where i break it up into multiple threads (Source -> Decoder -> Filter -> Encoder -> Sink) and trying to understand the complications

问题 I'm developing an application that makes calls to ffprobe that return the unorthodox exit status of -1094995529 for certain files when on Windows. This exit status is given consistently, and there is some minor discussion of this. Why is this value given, and where is it documented? Can I expect this status to be different on a unix machine where the allowed exit statuses are more constrained? 回答1: Error codes from ffmpeg (error.h from avutil) : http://ffmpeg.org/doxygen/trunk/error_8h_source

问题 I'm looking at re-muxing some containers holding audio and video such that I extract the best, first audio stream, and store it in a new container where e.g. only the audio stream is present. The output context for FFmpeg is created like so: AVFormatContext* output_context = NULL; avformat_alloc_output_context2( &output_context, NULL, "mp4", NULL ); I have a shortlist of acceptable outputs, e.g. MP4, M4A, etc … essentially those that are readable by Apple's Audio File Services: