>From: [email protected]
>To: [email protected]
>Date: Sun, 21 Jun 2015 13:57:30 +0300
>Subject: [Libav-user] avformat_open_input error with custom IO
>
>I am trying to implement a custom IO read, where I have some jpeg frames
>coming as byte array and I have to decode them for >later processing.>For now
>my function just read the first two successive frames, then the call to
>avformat_open_input return -1094995529
>uint8_t* buffer = NULL, * avioCxt_buffer = NULL;> buffer_data
>bd;> int ret = 0;>> bd.ptr = (uint8_t *) pJPEGFrame;>
> bd.size = len;>> // allocate the context data
>structure> if ( (*outputFormatCxt = avformat_alloc_context() ) ==
>NULL)> {> fprintf(stderr,
>"convert_JPEG_Frame_TO_AVFrame @line(%d) - failed to allocate memory for
>context", __LINE__);> return -1;> }>>
>if ( (avioCxt_buffer = (uint8_t *) av_malloc(len)) == NULL)> {>
> fprintf(stderr, "convert_JPEG_Frame_TO_AVFrame @line(%d) -
>failed to allocate memory", __LINE__);>
>avformat_close_input(outputFormatCxt);> return -1;>
> }>> if ( (*pAvIOCxt = avio_alloc_context(avioCxt_buffer, len, 0,
>&bd, read_packet, NULL, NULL)) == NULL)> {>
>fprintf(stderr, "convert_JPEG_Frame_TO_AVFrame @line(%d) - failed to allocate
>memory", __LINE__);> return -1;> }>>
> (*outputFormatCxt)->pb = *pAvIOCxt;> if ( (ret =
>avformat_open_input(outputFormatCxt, NULL, NULL, NULL)) < 0)> {>
> fprintf(stderr, "convert_JPEG_Frame_TO_AVFrame @line(%d)
>- failed to allocate memory", __LINE__);> return -1;>
> }>>I am following the avio_read example using the same read callback
>function for the avio context.>>Thanks in advance.
I tried to make a turn around after reading the source code of the library - I
am working on windows, I can't do much debuging.I found that the problem is in
the probe this function av_probe_input_formatthe return score for the first two
frames is correct its "jpeg_pipe"but for the other frames it return probe_score
= 1
so I made my turnaround by associating the iformat field of the AVFormatContext
using this code - I am guaranteed to have only jpeg files.
AVInputFormat * iformat = av_find_input_format("jpeg_pipe"); if
(!iformat) return -1; (*outputFormatCxt)->iformat = iformat;
And it worked fine!
I don't really understand the problem, nor I do understand what might be the
consequences of that turn around.
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