[Libav-user] Does the image2 demuxer work with a custom AVIOContext?

Paul B Mahol onemda at gmail.com
Fri Feb 21 12:54:41 CET 2014

On 2/21/14, Robert Krueger <krueger at lesspain.de> wrote:
> On Thu, Feb 20, 2014 at 3:01 PM, Paul B Mahol <onemda at gmail.com> wrote:
>> On 2/20/14, Robert Krueger <krueger at lesspain.de> wrote:
>>> On Wed, Feb 19, 2014 at 10:02 PM, Paul B Mahol <onemda at gmail.com> wrote:
>>>> On 2/19/14, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>>>>> Carl Eugen Hoyos <cehoyos at ...> writes:
>>>>>> Robert Krueger <krueger <at> ...> writes:
>>>>>> > cat ~/samples/fate/dpx/lighthouse_rgb48.dpx | ./ffmpeg
>>>>>> > -f image2pipe -vcodec dpx -i - ~/tmp/fromdpx_pipe2.png
>>>>>> > [dpx  <at>  0x7fcb21822600] Overread buffer. Invalid header?
>>>>>> The image is cut in the middle
>>>>> Iiuc, the parser reads the file size from the file
>>>>> header while the decoder calculates the (minimal
>>>>> possible) file size. The value that the parser
>>>>> reads from the file header is too small.
>>>>> I suspect the bug can be fixed by reusing the logic
>>>>> to determine the image size also in the parser or
>>>>> by ignoring the file size outputting everything until
>>>>> the next magic marker.
>>>> There is no bug in parser, bug is in dpx file which do not
>>>> conform to the specification.
>>>> FFmpeg dpx encoder is fine.
>>>> ImageMagick sucks.
>>> OK, I didn't know the file was generated using ImageMagick but I see
>>> it now. Then it is irrelevant for me and I will ignore this as long as
>>> valid dpx files work with this approach. Thank you for the analysis. I
>>> don't know what the sample is used for in fate but maybe it's there
>>> for testing broken dpx files. It just happend to be there when I was
>>> looking for a dpx file to test the image2pipe approach.
>> The sample is made before dpx encoder existed in ffmpeg....
> OK, if it helps I could generate some dpx samples for fate using
> Software like Adobe Speedgrade. Just let me know if there is interest
> in that.

Does such dpx files works with dpx parser?
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