如何在GStreamer中解码.tga图像？解码报错求助

文件信息 #

我尝试用GStreamer读取.tga文件并转换为视频，目前卡在TGA解码环节。该文件可被MacOS Preview正常打开，属性如下：

• 大小：8,294,418字节
• 分辨率：1920 x 1080
• 色彩空间：RGB Alpha（带通道）

文件大小符合计算值：1920×1080×4字节=8,294,000字节，包含合法TGA头部，是有效的无损图像文件。

尝试的解码管道及错误 #

我使用libav的avdec_targa解码器，执行了以下GStreamer管道命令：

gst-launch-1.0 -e filesrc location=/home/user/image.tga ! image/x-tga,width=1920,height=1080,framerate=1/1 ! avdec_targa ! videoconvert ! pngenc ! filesink location=output.png

运行后出现大量错误：

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
Redistribute latency...
0:00:00.025646827   656      0x2685c60 WARN            videodecoder gstvideodecoder.c:2425:gst_video_decoder_chain:<avdec_targa0> Received buffer without a new-segment. Assuming timestamps start from 0.
0:00:00.025789186   656      0x2685c60 ERROR                  libav :0:: Not enough data available for image
0:00:00.025815987   656      0x2685c60 WARN                   libav gstavviddec.c:1864:gst_ffmpegviddec_handle_frame:<avdec_targa0> Failed to send data for decoding
0:00:00.025842800   656      0x2685c60 ERROR                  libav :0:: Not enough data to read header
0:00:00.025856014   656      0x2685c60 WARN                   libav gstavviddec.c:1864:gst_ffmpegviddec_handle_frame:<avdec_targa0> Failed to send data for decoding
0:00:00.025874318   656      0x2685c60 ERROR                  libav :0:: Bit depth 186 is not supported
0:00:00.025887348   656      0x2685c60 WARN                   libav gstavviddec.c:1864:gst_ffmpegviddec_handle_frame:<avdec_targa0> Failed to send data for decoding
0:00:00.025897921   656      0x2685c60 ERROR                  libav :0:: Not enough data to read header
0:00:00.025909691   656      0x2685c60 WARN                   libav gstavviddec.c:1864:gst_ffmpegviddec_handle_frame:<avdec_targa0> Failed to send data for decoding
0:00:00.104450817   656      0x2685c60 WARN                   libav gstavviddec.c:1864:gst_ffmpegviddec_handle_frame:<avdec_targa0> Failed to send data for decoding
0:00:00.104466306   656      0x2685c60 WARN            videodecoder gstvideodecoder.c:1140:gst_video_decoder_sink_event_default:<avdec_targa0> error: No valid frames decoded before end of stream
0:00:00.104473182   656      0x2685c60 WARN            videodecoder gstvideodecoder.c:1140:gst_video_decoder_sink_event_default:<avdec_targa0> error: no valid frames found
ERROR: from element /GstPipeline:pipeline0/avdec_targa:avdec_targa0: No valid frames decoded before end of stream
Additional debug info:
../../../../../../../../src/Gstreamer-plugins-base/gst-libs/gst/video/gstvideodecoder.c(1140): gst_video_decoder_sink_event_default (): /GstPipeline:pipeline0/avdec_targa:avdec_targa0:
no valid frames found
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...

我对此感到困惑：根据计算，该图像位深为32位，但libav却识别为186位，希望得到解决提示。

补充验证信息 #

我用Python Pillow库读取该文件，代码如下：

from PIL import Image
with Image.open("imageFrame_0001.tga") as img:
    for attribute_name in dir(img):
        attribute = getattr(img, attribute_name)
        if not callable(attribute):
            print(f"{attribute_name}: {attribute}")

得到的元数据：

'version': 3
'shape': (1080, 1920, 4)
'typestr': '|u1'
'mode': 'RGBA',
'info': {'orientation': -1},
'tile': [],
'decoderconfig': (),
'decodermaxblock': 65536,
'fp': None,
'filename': 'imageFrame_0001.tga',
__module__: PIL.TgaImagePlugin
_category: 0
format: TGA
format_description: Targa
info: {'orientation': -1}
mode: RGBA
readonly: 0
size: (1920, 1080)
width: 1920
height: 1080

内容的提问来源于stack exchange，提问作者Xiangyang Shi